langzi's Journal

Authors: Payton Curley, Evan Gray, Jasmine Rosado, Julianna Evinski
Introduction:
The objective of this monitoring project was to collect data on the richness of fish families and invertebrates both within and in areas surrounding the fish pond. We were tasked with creating a cumulative list of all the species found in four locations: inside the refuge, within the fish pond in general (excluding the refuge), directly outside of the fish pond’s borders, and further away from the pond in the reef area. Species richness—or species count—in an area is important because it can be an indication of biodiversity. We analyzed species richness in the fishpond and made comparisons to the outside, calculating the number of species per square meter for every area in the process. This information can be used to compare to past years and analyze changes in diversity. We can draw conclusions about overall health and activity of the fishpond, as well as changes over time based off this information. The monitoring of this pond officially began 2 years ago and our group is excited to contribute to this monitoring project.

Methods:
Our areas of focus consisted of inside the fish pond, the exterior of the fishpond wall, the outer coral reef, and the new refuge in the fishpond. For the inside of the fishpond we decided to conduct a preliminary simple floating survey to get a gauge of what species we should be looking for. The next day we decided to use the transect beam method to quantify the number of species in the pond. We used 3 transects--one for each wall--each 15 meters long. We began by measuring 1 meter away, perpendicular to the wall, to establish the start point on the transect and staked it down in the sand with a rock. A researcher then ran it parallel to the wall and swam an extra few meters past the other end so as not to bother fish directly in the 15 meter survey area. After waiting 2 minutes, another researcher would then swim along the transect, recording any pelagic fish seen 1 meter on each side of the transect below, covering a total of 30 square meters per transect. After swimming the length of the transect, the researcher would then wait another 2 minutes and then swim back over the transect, this time recording benthic fish and invertebrates.
To survey the outer border of the fish pond, we used the same method, instead measuring 1 meter away from each wall on the outside of the pond. We then ran each 15 meter transect parallel to the wall and recorded pelagic and benthic species, as well as invertebrates.
To survey the outer reef away from the fish pond, we used three different areas. The first area we measured was 15 meters away from the left wall of the fishpond. We laid a transect out parallel to the wall, repeating the same methods to measure fish species. We then measured 15 meters away from the border wall and laid out another transect parallel to the fishpond and repeated the survey methods. We then measured 15 meters away from the right wall and laid out another transect, repeating the same methods for measuring fish species.
We also measured the fish species in the newly built refuge. One researcher started a 10 minute timer, watched the fish swimming in and out of the rocks surrounding the refuge, and took note of the different species. After the first 10 minutes were up, the researcher then started another 10 minute timer and watched the fish that were inside the refuge and in the boulder.
In conducting this survey, there were a couple changes from the previous year's group that observed fish biodiversity. Although we used the same methods for surveying the inside of the pond and on the border of the wall, we changed the method for the outer reef survey. The previous group decided to use coordinates and do 3 transects parallel to shore at that location. We decided instead to survey 3 different locations, each parallel to one of the walls of the fishpond. We changed this because we believe that surveying different locations for the outer reef would give a more accurate depiction of the greater lagoon that the fishpond is a part of. We wanted to eliminate possible confounding variables as factors like the strength of the current and depth vary based on where you are in relation to the fishpond. This is why we decided to include two areas off the beach on either side of the fishpond as well as one further into the water from the outside wall. This way we could see how the fishpond affects the greater ecosystem.
In addition to these changes, we also decided to focus solely on species richness rather than richness and abundance due to the fact that our client was most interested in which species were present rather than the amount of individuals we saw. Another addition to our methods in comparison to the previous year was focusing on invertebrate species as well. The method that we chose for surveying fish species works for invertebrates, which our client was interested in seeing in addition to the fish species.

Results:
INSIDE
It consisted of 16 different species making up 9 families. Damsel, Soldier, Surgeon, Cardinal, Lizardfish, Wrasse, Butterfly, Trigger and Goat. The main families were Butterfly, Wrasse, and Damsel. There were also a few invertebrates in the pond that were recorded, which were burrowing urchins and cone snails.
BORDER
We found 12 species and 6 families. The families we saw were wrasse, damselfish, butterflyfish, goatfish, triggerfish, and snapper. The dominant fish families in that area were the wrasse, damselfish, and butterflyfish. On the border there were invertebrates like urchins, sea cucumbers and snails.
OUTER
We found 8 species and 6 families outside of the pond. Those families were wrasse, triggerfish, damselfish, butterflyfish, goatfish, and blenny. The dominant fish families were wrasse and damsel. The invertebrates that were seen were sea cucumbers and urchins
Species per square meter:
In the outside of the pond the fish species per sq meter is 0.267 and the family per sq meter is 0.2. The border of the fish pond species per sq meter is 0.4 and the family per sq meter is 0.2. Inside the fish pond the species per sq meter is 0.533 and the family per sq meter is 0.3.
REFUGE
The refuge has a 5.26M^2 area and the species found in the refuge were convict surgeonfish, vagabond butterflyfish, dusky gregory damselfish, scribbled rabbitfish, and shrimpgoby. The species per meter squared is 0.95.

Excel Sheet of Fish species and families in the areas we surveyed and the refuge: https://docs.google.com/file/d/1m8wKrIt85X0fUAqYR5jy4uCnl2dJ0mCe/edit?usp=docslist_api&filetype=msexcel

Graphs of the Dominant fish families in each area surveyed: https://docs.google.com/document/d/1-TLTvTTL0N2qam0O5UhaSUtxwH7bV46unkOpq7_5_dE/edit

Discussion:
After the survey, it was determined that there was a greater diversity of fish species inside the pond versus near the pond and 15 meters away from the pond. The diversity of the fish species gradually decreases as you get farther away from the pond within the area that we surveyed. This is different from last year's findings where there was a higher diversity of fish species outside the fish pond. However, it is important to note that our locations outside the fishpond were in similar depth of water to the fishpond itself, and it is possible that last year surveyed a deeper area of the lagoon which would have affected the fish species they saw. In addition to this, we saw a overall increase of families of fish in all of the sites compared to last year
Compared to previous years, this year our client was less concerned with abundance and wanted to focus more on species richness. With the list of species we have curated at the request of our client, we have categorized them into families. This can be helpful to know because we have learned previously that members of different families exhibit different behaviors and it can be telling of the nature of the ecosystem interactions between fish and their environments. Ultimately with the species list, we hoped to create a bigger picture regarding species interactions. We ended up finding there was an increase in the number of species present using the same transects inside of the fish pond as last year. This increase in species richness could be occurring because of a number of reasons, including the recent swell. Our client mentioned there had been a buildup of algae and sediment in the area, and the swell washed some of these materials out to some degree. We imagine this event cleaned up some of the area, thus increasing the health of the fish pond, bringing more species back into it. Additionally, as time goes on naturally, the fish pond will gain popularity among the fish. As the ecosystem becomes more established, more species will be drawn into the pond. When juveniles come in, this attracts bigger fish and causes a cascade effect of abundance. If conditions in this area remain the same, diversity will likely continue to increase over time. We hypothesize that if the survey was to be repeated next year, the species richness will continue to increase.
We are considering our measurements as time zero for the refuge since it was only established a few weeks ago. Our client was interested in seeing how smaller, more sheltered areas would affect the biodiversity of fish in the location. We have already noticed a variety of different species and families within the refuge and within a meter of the perimeter wall. We calculated a high species per square meter value which is telling of the importance of micro-habitats and how they foster fish biodiversity.
The limitations of our experiment mostly had to do with the physical constraints of the ocean. During our first day of data collection, the tide was low and thus the water level in the fish pond was abnormally low. Still, we stuck to our methods and continued to use the transect to allocate our two meter wide survey area. As a result, some areas were too shallow for fish to be located in–namely the left and right transects inside the fish pond which ran perpendicular to the shoreline. If we had more time to collect data, we would have waited until the tide was higher. Additionally, the current in the area was strong–especially on the first day of data collection–so the transact lines may not have been completely parallel to the walls of the fish pond. Like with our first limitation, if we were given more time, we would have waited for ideal current conditions. Our final limitation is due to the nature of observing fish in the wild. As shown in our data table, some of the species were not fully identified due to the limited amount of data we had—fully relying on memory recollection while collecting data. Therefore, both the stonefish and the shrimpgoby were identified solely by their family name instead of being more specific and identifying their species. Going forward, we would recommend to future researchers to either invest in waterproof identification guides so as to be able to identify species while still in the field or bring a camera along with them while surveying.

SURVEY DATES: 05/19/2024 - 05/21/2024
SURVEY LOCATION: Paea Lagoon Aua i’a Fish Pond
AUTHORS: Jessie Segnitz, Uma Pant, Nicole Pianalto, and S. Tara Grover

INTRODUCTION:
In this survey, we observed the substrate inside, on top, and outside the Paea Lagoon Aua i’a Fish Pond. The fish pond is a Polynesian traditional practice of small scale fish collection that fell into disuse over time due to the effects of European colonization, commercial fishing, and globalization. We are building upon the previous studies done by Wildlands students in 2022 and 2023 in order to meet the needs of our client, a private individual interested in species and land conservation who owns a marine observatory on Tahiti.

The objective of our study is to determine the sea floor substrate and algae covers on the inside and outside of the fishpond, and top of the rock wall top itself. Further objectives of the research team were to establish measurement definitions for the average particle sizes of both "fine" and "coarse" sand to set a standard for future use, and second, evaluate the presence of patterns on the seafloor of fine and coarse sand areas. There is a current along the shore running south to north through the fishpond and our client is specifically interested in the influence of this current and how the rock wall may act as a sieve or filter, changing the concentration of the sand types on the different sides of the wall. Earlier studies concluded that there was no statistically significant difference in substrate coverages outside and inside the fishpond, however, they did not account for the difference between fine and coarse sand, which is the knowledge gap we addressed with our survey.

We hypothesized that there would be a significant difference in the coverage of the different sand types on the south and north side of the wall. We further hypothesized that there would be a difference in overall substrate coverage inside and outside of the fish pond walls because of the barrier effects of the wall on the current's ability to move and transport substrate types through the area.

METHODS:

FIRST SURVEY — INSIDE FISH POND
We used a 50 x 50 cm quadrant to survey percent coverage of different substrate and algae types. We used a random number generator to generate 10 coordinates within the size of the fish pond which is roughly 15 x 15 meters. Using the bottom right corner of the fish pond (Northern corner) as our (0,0) origin point, we used a transect to measure out the predetermined coordinate points to the South along the shore (x-axis) and out into the water (y-axis) and placed the bottom right corner of the quadrat at each point. Our randomly-generated coordinates were (8, 12), (5, 1), (2, 7), (10, 9), (14, 3), (9, 11), (6, 12), (7, 9), (12, 9), (13, 2).

For this survey as well as Survey #2, we evaluated percent coverage of the following categories: fine sand (with the majority under 1mm length of grain on average), coarse sand (over 1mm length of grain on average), bare rubble (chunks of substrate between 2.5-10 cm, including stone, dead coral, shells), bare rock (over 10 cm with no algae cover), and five types of algae. These types were turf algae (under 1 cm), and the macroalgae genuses: Halimeda, Padina, Turbinaria, and Dictyota. Two researchers both independently estimated the coverage of each type and then double verified with each other.

We made sure to step lightly to avoid disturbing substrates or moving any particles into or out of the quadrats. We also exercised a high level of caution to avoid contact with dangerous benthic species including the stonefish, by wearing neoprene boots and swimming when possible without touching the floor.

SECOND SURVEY —OUTSIDE FISH POND
Starting from the north fish pond edge at the point closest to the shore, we measured out 5 meters parallel to the shore. That would be our starting point of our survey line of 15 meters to the end of the fish pond walls. We did systematic sampling, so every 5 meters starting from 0 meters on the transect we would sample using a 50 x50 cm quadrat, putting the quadrat on the left side of the transect with the bottom right corner at the starting point. We did this for the north, west and south walls of the fish pond. We evaluated percent coverage of the same categories and methods as for Survey #1 (above).

THIRD, FOURTH, AND FIFTH SURVEY — SEDIMENT TRANSECT
In this survey we used line intercept sampling by using a transect adjacent to the interior and exterior wall, which we identified as the area on the seafloor closest to the rock wall that did not include any large rocks that made up the foundation of the wall. We evaluated percent sediment coverage of the following categories: fine sand (under 1mm length of grain on average), coarse sand (over 1mm length of grain on average), rubble (2.5-10 cm), rock (greater than 10 cm), and alive coral, all regardless of any algae cover on top. By looking at what sediment lay directly underneath the transect line we classified what sediment was present and the length of the section it created, for the entire 14.5 meters. We conducted this survey for the north, west and south side walls of the fishpond on both the inside and outer side of walls.

SIXTH SURVEY—- ON TOP OF WALL
For this survey we used systematic sampling using the 50 x50 cm quadrat and a transect laid out from the start of the rock wall for all three walls. We placed the bottom of the quadrant at 0m, 5, and 10 meters for each wall. The quadrat was placed in the very center of the wall, and at all survey points, the wall was thicker in width than 50 cm so the quadrat consisted completely of substrate from the wall itself. We looked down from an aerial view and measured the same substrate and algae types as previously mentioned in the other surveys. We repeated this method for all three walls for a total of 9 survey points.

SEVEN SURVEY — SAND MEASUREMENT
For this survey a team of two took samples of fine and coarse sand from inside the fishpond, scooping only the surface layer of sediment. We collected approximately 20 mm of sand and water for each. The samples were chosen based on visual differentiation, where the fine sand was scooped
from the left wall delta closest to shore inside the fishpond, and coarse sand from the center of the fish pond. The sand was laid out on a paper towel and a randomization method was used to choose 50 grains of sand to measure from each sample. Calipers were used to measure out the various particles in millimeters.

IMPROVEMENTS/ CHANGES FROM PREVIOUS SURVEYS

We used a 50 x 50 centimeter quadrat instead of the previous group's 1x1 m. This allowed us to take more accurate and detailed data on the coverage within our survey areas while still being a large enough surveyed area to be generalizable to the entire pond.

We know that the algae species and concentration can change due to seasonal and climate patterns. We did our own preliminary analysis of what types of macroalgae genuses were present when we got in the water, and created our own list of them to measure instead of using the previous groups. This was the same as the previous groups except for one exclusion, Sargassum, which was not present at this time, and one new inclusion, Dyctyota, which was present.

We did a randomized point intersect method for the inside of the fishpond instead of the previous groups' strategic sampling method because the fishpond is a big enough sample universe to benefit from a random sample to eliminate bias or accidental disproportionate inclusion or exclusion of substrate patterns.

We continued the original method of strategic sampling for the outside fish pond sampling universe, and for the walltop itself, because we felt that the narrow range of these areas would be better represented by consistent sampling. A visual analysis of the general substrate cover of the entire survey area confirmed that we were not overlooking any patterns due to this sampling method.
Surveying the wall top itself was also a new addition to this survey project that was not present in previous years. This allows us to set a baseline time zero (t=0) standard for wall composition which gives insight into the structural integrity of the stones based on how close together they are, and what substrate types are present among the cracks..
Another new addition was the specific line-intercept survey along the outer and inner walls that focused on determining patterns of sand dispersal through the walls.

RESULTS:

Please copy and paste the link below into your browser to view data sheets with graphical analysis

https://docs.google.com/document/d/1296DmEP9zlzIvRDUheGtx5jx7ANnlSfT8JGAyNMvuSI/edit

DISCUSSION:

Survey one data illustrates that the substrate cover inside the fish pond is mostly coarse sand and a scattering of rubble across the area. While the dominant algae inside the fish pond was Halimeda. In the survey two data, it portrays that the sediment composition outside the fishpond was mostly made up of fine sand and some coarse sand, while the algae was mostly turf. The differential sediment composition inside and outside the pond demonstrates that the fish pond creates a different sediment environment, which is reflected by the dominant algae that is growing in the area.

The survey three, four, and five data show sand patterns that are representative of the current flowing through the pond. The currents are coming from the south going north, parallel to the shore. Outside the southern wall there was a larger section of fine sand, while the interior of the fishpond there were three distinct sections of fine sand. This illustrated that the southern wall is filtering the fine sand into the pond at a relatively slow rate, with most of it concentrated on three sections that correlate with thinner and lower wall sections. While on the other hand, the opposite was reflected by the north wall, by the sand filtering out of the pond. The exterior of the wall substrate consisted of more fine sand than the interior of the wall reflecting that there is a large rate the fine sand is leaving the fish pond. With the influx of fine sand coming in at a slower rate and the outflux leaving at a greater rate, the inventory of the fine sand in the fish pond would be lower. This is also reflected in the data from survey one, the sediment coverage inside the fish pond, portraying that there was very little fine sand within the sampling sites that is a portrayal of the entire pond. Then with the west wall the sediment makeup of the interior and exterior was fairly similar with the percent of fine sand being around 30 percent. This similarity illustrates their is not that much if any sand movement between this wall.

For Survey 6 looking at substrate composition on top of the wall itself, we found that the turf (algae less than 1mm long on top of rock/rubble) dominated the bulk of the substrate available in this location, at 83%, as expected. The wall is composed of large rocks, and can resist wave action more so than coarse or fine sand, which can be washed away. Since the stones here are the original foundation of the fishpond from whare our client rebuilt it many years ago, it makes sense that turf covers almost all of the present stone content. The coverage of bare rock with no turf is only the parts of stones that are still above water even at high tide, so there was no ability for turf to settle and grow there. The areas that were not turf or stone are what is visible between the rocks when looking from an aerial view, ad thus they represent the cracks between the rocks which allow a view of algae content below and occasionally all the way down to the sand on the floor.

During Survey 7, we revealed key information about classifying the difference between the size of coarse and fine sand. We found that the coarse sand had a median of more than 1mm in particle size, and the fine sand had a median size of less than 1mm in particle size. We used this understanding to clarify our data for both types of sand during the other survey collections, where we used visual markers to identify each type. This classification can also be used for future studies as a standardization of the monitoring project.

It's important to note there was an ocean swell a couple weeks ago that washed away different substrate from the location that may have previously been present in the area. For example, certain algae species and fine sand may have been washed away, influencing the current composition of the inside and outside of fishpond wall barriers. This may contribute to significant differences between this survey and the previous ones, although other factors such as seasonal differences and simply the regular wave and wind action of many months will also produce these differences.

Overall, there are noticeable trends in the differences with sand cover on the inside versus the outside of the fishpond.
The higher concentration of fine sand outside could be due to current and wave action pushing coarser, heavier sand particles inside the fishpond that has nowhere to go, whereas Fine sand can be lifted away by wave action. The fact that turf on rock substrate covered most of the fish wall shows how the stones have been present long enough to accumulate turf cover.
Another explanation for the lack of other types of substrate and algae coverage may be due to the nature of intertidal zone harsh conditions, which only support life for the most hardy species that can survive high and low temperatures, water and salinity levels, and have increased mechanical wave action that make it difficult to establish a presence on the rocks and moves sediment rather quickly, not allowing for settlement.

We also noted an interesting observation from this year's data versus last year's projects. Halimeda is the most common algae found in and around the pond, which is different from the rest of the coral reef areas that the research team has seen across Tahiti and Moorea.

PROPOSALS FOR FUTURE METHODS:

We propose that future projects continue to differentiate between fine and coarse sand, so that a standard can be maintained for data collection over time in consideration of factors such as current speed and wave action.
A proposal for future groups is to analyze the structure of the wall to determine what qualities exactly lead specific sections to allow more fine sand through the stones.
The line-intercept survey of sand cover along the sides of the walls should be repeated to track change over time.
We also recommend separating the data collection between algae biodiversity (different genuses) and mineral substrates (coral, sand types, rock, rubble) as separate surveys, where the mineral substrate survey does not regard algae coverage.
The algae biodiversity survey should also include a difference between turf on rock vs. turf on rubble, to make sure that it is clear to differentiate the preferential turf substrate.

We also recommend continuing data collection on specific algae types over time, or making sure to note if there is a decrease in a specific population during that year to maintain standard measurements, just to keep a clear comparison of the different populations in the fish pond over time.

By Elyse Hartmann, Madeleine Yang, and Marina Thompson
Survey dates: 5/19/24 - 5/21/24
Location: Paea, Tahiti, French Polynesia

Introduction
In this study we started a beach profile to monitor how the beach elevation changes over time. The objective given was to measure the degree of which the terrain slopes by looking at transects going through the Paeanfish pond and outside of it, by our client Thomas. Our monitoring reveals information on the relationship between current and sand deposition, as well as documenting erosion.

Methods
We started by measuring the dimensions of the fish pond. Each wall of the fish pond and the opening on the beach were measured to the outermost part.
In order to get a representative profile of the beach’s elevation, we split the area into four, parallel, 32 meter transects with 5 measurements taken within. Two transects went through the fish pond and two were on either side of the fish pond walls.

To gather the measurements, we used the south most noni tree in front of the pond as a fixed point to standardize the starting point for measurements. In the future if this tree is no longer there, start measurements 0.34m to the left of the southern mist metal pole in front of Thomas’ property. To calculate the slope of the beach, tape lines 120cm high on two sticks were used in conjunction with a protractor: we recorded the angle from the higher stick to the lower stick by looking at the other tape mark through a straw on a protractor. The protractor had a string with a weight attached to it, so one team member could read the angle indicated by the string, while one was looking through the straw. This was repeated to get the angle and hypotenuse 20 times around the fish pond in a systematic manner. Then the height from the original (horizontal point near noni tree) was calculated using cosine.

In order to measure the speed of the current we strategically choose five spots around and within the fish pond, making sure to intercept all the previous four transect lines. We took measurements on each side of the fish pond’s interior (north and south), two outside the fish pond’s walls (north and south), and one west of the fish pond outside the walls. At the spot, one team member held each side of the tape measure and the third team member recorded the time of when the buoy went past the designated marks. The buoy was dropped at 0m and floated downstream to pick up speed, once it reached 3m a stopwatch was started. When the buoy reached 7m (a distance of 4m recorded) the stopwatch was stopped and the time was recorded. The data was then averaged to find the speed in meters per second (m/s).
Safety precautions such as wearing shoes were taken when walking in the lagoon to avoid complications with venomous benthic animals.

Results
NOTE: Our depth measurements are not correct. We have determined that our measurements are proportional to each other and the beach slopes and current speeds are correct. (Therefore, figures 2-3 and 5 are all correct). However, the depth measurements do not reflect the real depths from point zero, so figure 1 is visually correct, but numerically incorrect. This is due to an unknown error in methods or calculation. We suggest future groups look further into this.

The measurements of the fish pond walls were 14.5m in the South wall, 17.1m for the East opening, 15.7m for the North wall, and 16.8m for the West wall.

Figure 1 shows cross sections of the beach along four different lines. It shows that the southmost line (site 1) has the lowest depth at the start and highest depth before the waterline. Whereas, the part of this beach cross section that is below the waterline has the second largest depth from point zero. If you look at site 2, the opposite is happening, the depth is the 3rd largest before the waterline and the shallowest after the waterline. Site 3 on the northern side inside the fishpond has the greatest depth throughout the whole transect line with the deepest part at 5.32 meters below the wall of the property.

These results correspond with calculations of the slopes showing that site 3 has the greatest negative slope overall of -0.22 and Site 2 has the lowest negative slope of -0.13. All of the slopes within each transect line had standard deviations between 0.08 and 0.15 showing a large amount of variation in slope within each site line. Though, transect 3 had the most slope variation.

In addition, the ocean currents at each location along the transect line sites differed. The current speed was highest deeper into the water west of westward fish pond wall where the current speed was 0.36 m/s. This is to be expected since the measurement was taken much deeper into the water. Location 1 was the next greatest along transect one (south most outside the fish pond) with a speed of 0.17 m/s. The lowest current speed was measured at site 2, where the average slope was the lowest as seen in figure 2. T-tests showed that there was a significant difference between the current speed between sites 1 and 2 with a P-value of 0.072.

Figures: https://docs.google.com/document/d/1s2taUzmCdVAy7Pd_E-1flnjZBLYdMdLJDsTSKIdLg3o/edit

Figure two represents the average slopes of our four transect lines. Site 3 had the greatest slope and figure two had the smallest. These were both the transects within the fish pond.

Figure 3 depicts the different current speeds at 5 locations, three outside of the fish pond and two within. Locations 1, 2, 3, and 4 each intercept the corresponding depth transect perpendicularly. Site 5 is parallel to the west wall, and had the highest current speed.

Figure 4 is useful in visualizing the different depths from the starting spot at different points in and around the fish pond. The depths ranged from .3 to 5.32 meters. The scale of colors goes from white/yellow (shallow change), to red/purple (deep change).

In order to establish long term visuals of how the fish pond changes shape and the walls shift, we took a photo standing from a perch on the bathroom wall. Future photos can be compared to this baseline- 5/21/24.

Discussion
Our results present a couple different patterns and findings that could be relevant to continue monitoring overtime.
The south side of the fish pond interior has a shallower depth and slope than the north side interior. Correlating this finding with lagoon current strength and direction can tell us about the possible future of deposition of sediment and changes of depth within the fish pond. The measurement can be used as a baseline measurement and repeated in the future to compare and quantify changes occurring within the fish pond.
Specifically, we found that the current is traveling northward, and we recorded a 0.6 meters per second slow down after the water crossed the south wall of the fish pond. Therefore, the higher elevation on site 2 can be correlated to sediment deposition due to slowed current speed after the fish pond wall.
Additionally, we want to note the relationship between the largest depths (at site 3), and the hole in the fish pond’s west wall, which overlaps with site 3. We observed that when a buoy was placed in a few meter’s radius of the opening, it would float towards that exit, slowly increasing in velocity, exemplifying this as an outflow spot for currents. This could help explain why the north interior side of the fish pond is deeper than the south, because of sediments being carried with currents leaving the pond at this exit (and other cracks and crevices along the north wall).
Numerically we recorded an average 0.3 meters per second increase in current speed on site three compared to site 2. But it’s relevant to note that we did not calculate current velocity specifically at the mouth of the west wall opening - which is where it would have been even faster, as observed visually by buoy movement. This solidifies the relationship between current direction, velocity, and deposition of sediment in and around the fish pond, especially when considering different physical features.
In the future we suggest groups do more measurements around the hole in the west wall. These could be current, depth, or sediment related to learn more about the erosion and deposition occurring in the fish pond and around the opening.

Errors
As this is the first beach profile there were a couple of human errors that can be addressed. One error would be that when measuring the dimensions of the fish pond we were at the water level. This may cause error as we may have not been aligned with the fish pond walls.
During the days that data was collected there were varying wind speeds between 3 and 5 on the Beaufort scale. We recorded the wind speeds at the time of each current trial in order to include a more accurate depiction of what was happening and why.
The wind made it difficult to fully straighten long transects and made it difficult to use the string method on our protractor when calculating angles of the topography’s slope. To reduce error, one person would look through the protractor while another person ensured the weight at the end of the string was indeed oriented downwards.
The large swell two weeks ago and other temporal weather could have affected the depth of the sediment and the current speeds.
In addition, there was an unknown error during data collection and processing, influencing the accuracy of our data.