Fish Biodiversity and Behavior Patterns- Fish Pond Monitoring Project FP 2023

INTRODUCTION:
The objective of our fish pond monitoring project was to collect data on the behavior and biodiversity of fish families that are found inside the pond, near the pond. as well as in outer regions of the reef. Since the topic and goal for the monitoring project was already given by the previous group, we altered their methods to increase accuracy and precision of the study.

METHODS:
Our methods changed slightly from the past years. To conduct our experiment we measured 3 sites: the inner fish pond, the exterior of the fish pond, and the outer coral reefs. We used transects to collect our data and had two researchers hold the transects at 15m of length while the other 2 researchers swam on either side of the transect, observing the area below them that went 1m out from the line (therefore 30m^2). Three of these transects were taken per site. The recorders swimming noted different fish species, amount of fish per species, as well as the behavior the fish performed when first spotted on the recorder’s swim. Each transect swim took about 3 mins.
To place the transects in the inner pond when facing the water, one transect was along the left wall, one along the right wall, and one at the centerline of the fish pond, also perpendicular to the shore.
The transect of the outer pond simply lined the outer section on the pond going 2m beyond the fish pond structure along the left, back, and right wall.
The outer coral reef collection site was at 328, 05 according to Tomas’ camera determined by a buoy placement that was swam out through the use of a scuba jet. The buoy was placed at approximately 17° 42' 27" South 149° 35' 11" West. Three transect lines were placed perpendicular to the shore mimicking the inner pond formation (each line being 6.5m apart with the center line starting directly on the buoy).

To analyze our data we compared behaviors in the different sites through percentage breakdown and also used a Shannon’s index to find differences in fish species diversity.

Compared to last year (what changes and why)
-Using transects to swim across to count fish and observe their behavior instead of a 20 minute floating survey of a given area to avoid fish recount and for unbiased collection
-The location of observations that were analyzed outside of the fish pond because we wanted to have a better scope of the area between the shore and the wave breaks. Going to the farther reef was also requested since the fish pond ecosystem is supposed to mirror that of a reefs
-The use of statistical analysis to support any anecdotal observation (ie Shannon’s index and percentage comparisons) because beforehand there wasn’t much data we could go off of and compare to, just general observations. Data collection provides a concrete comparison for people who will replicate the experiment in the future

RESULTS

General fish spread
We saw mostly damselfish, wrasse, and Butterfly fish. In both the outer and inner pond damselfish were the dominant family while wrasse was the majority in the outer reef with damselfish second. We saw a wider variety of fish families in the outer reef where we saw 11 families compared to the inner and outer pond which had 7 and 5 families respectively.

Shannon’s index
The calculated Shannon's index in the outer reef was 1.63, 1.26 in the outer pond, and 1.19 in the inner pond. This supports the fact that diversity was highest in the outer reef compared to the inner pond.

Fish per square meter
In the outer reef, we found 2.23 fish per square meter, outside the fish pond there were 1.104 fish per square meter, and inside the pond there was less than 1 fish per square meter. This information shows that the outer reef also had higher abundance than the other two sample sites.

Behaviors in each area: Top percentages of each behavior

Lagoon- 44.3% were freely swimming, 19.9% were territorial, and 16.4% were eating coral

Outer pond- 41% were freely swimming, 25.6% were territorial, and 12.8% escaped

Inner pond- 47.2% were territorial, 33% were freely swimming, and 10.4% were eating algae

Which behaviors were done by fish families: Top percentages

Lagoon:
Territorial fish - 100% were damselfish
Swimming fish - 58.4% were wrasse and 20.2% were damsel
Coral eaters - 81.8% was an unidentified fish that we think is a juvenile parrot fish

Outer pond：
Swimming fish - 40% were damsel, 28.6% were goat fish
Territorial - 92% were damsel, 6% were soldier
Escaped, 90% were damsel, 10% were butterfly

Inside pond:
Territorial - 100% were damsel fish
Swimming - 56.2% were damsels
Algae eaters - 100% were wrasse

Discussion

Overall, our group found that there was a higher diversity in the outer reef than the inner pond as well as the two meter perimeter surrounding the pond, which was also observed by last years group.This is reflected by our Shannon’s index values, where the outer reef value was greater by 0.44. Additionally, we observed a higher abundance of fish in the outer reef, which is seen in our data concerning fish per square meter, where the outer reef had about 4.5 times more fish per square meter than the inner pond.

We hypothesize that biodiversity is greater in the outer reef because there’s a significant difference in coral abundance, which acts as a resource for food and habitat. Next, we saw the the most predominant behavior was freely swimming except for in the pond where the top behavior was territorial. Territorial was the next most common behavior in the other areas as well. Damsel fish were most predominant in the territorial behavior category. A notable thing we noticed was that there was a high amount of damsel fish inside the pond made up of Gregory and the banded sergeant. We saw a disproportionately large amount of territorial behavior inside the pond compared to outside the pond where we sampled more wall space which tended to host territorial behavior.

We hypothesize that higher territorial behaviors in the pond could be related to the size of the pond. The smaller space may cause competition for resources and habitat.

Our biggest take awaysys were that damsel fish were a dominant family inside of the pond leading to high levels of territorial behaviors. This is a similar finding as last years group. Additionally, we noticed a higher percent of damsel fish inside the pond compared to outside the pond and the outer reef also similar to last years group.

https://docs.google.com/document/d/1-lte3bJXD-KZUitAeGB48uavjCKzf1KFa8uRnnCQIVM/edit?usp=sharing

Posted on August 4, 2023 12:51 AM by langzi