Fishy Regulations? More Like Fishing Regulations!

My summer project at Biscayne National Park will be calculating which fish species, if any, have the most fishing violations.

This study will focus on what is happening inside the park, therefore I will use creel surveys conducted by BNP. New fishing regulations were put into effect July 1st, 2020, so I will be using survey data from that point onwards (With the exception of 2020, due to lack of survey entries). The expected results are that some of the most affected species are the ones with stricter regulations on them, like mangrove snappers, blue striped grunt, and gray triggerfish. My goal is to corroborate these expected results or find discrepancies in the data. I am still familiarizing myself with the data, so I have no hypothesis as to why the results could be what they are.

The new 2020 fishing regulations in BNP. These regulations add new size limits to nine species of fish, bringing up the minimum required length by 1-2 inches.

 

To start off, we collect a lot of data during creel surveys: number of fisherman, how long they were fishing, where they were fishing, what were they targeting, what they ended up catching and/or releasing, and measuring how long the fish they caught was. Aside from collecting the data above, we also note any violations in the catch. These violations vary from bringing in egg-bearing crustaceans to harvesting ornamental species, to fileting fish offshore and harvesting undersized fish.

Biscayne National Park has their own set of rules and regulations for fish, on top of the ones that exist in the state of Florida (as depicted in the picture to the left). These regulations are stricter and are put in place to try and ensure the quality of fish present in the national park. There are ten species that are affected by these stricter regulations and many more that are affected by the park-specific 10-fish aggregate bagging limit.

 

A surprising challenge that has arisen while collecting this data has been converting measurements. On all regulation websites or flyers, the size limits are total length of fish and in inches. The issue is that during creel surveys fish length is recorded up to the fork of the fish’s tail, also known as fork length (FL), in centimeters. This is done because it is easier and more consistent to measure, as opposed to measuring total length (TL), which involves pinching the fish’s tail or flattening it as much as possible. 

In order to make sure all the fish measurements are accurate I have had to use an equation that can calculate fish TL from FL. This equation is a + (b*FL in inches). The a and b values differ for every species, so getting the TL has been complicated. An unnecessary step to this conversion has been having to convert FL from centimeter to inches in order to calculate TL. I made a conversion chart for all the fish listed with regulations on the Florida Fish and Wildlife website. The conversion chart shows the minimum fork length in centimeters needed for the total length of the species, allowing me to have a simple reference sheet while I continue to look over survey data and conduct future surveys. 

Two images: Top image shows an example of a fork length measurement with a hogfish. Bottom image shows ana example of total length measurement with a mutton snapper.

I am very interested in what I will find at the end of this research. I am also excited to tackle the challenges that might arise while working on this research. My hope at the end of the day is that this project will be able to contribute to the park. Like, looking into offering more protection of certain fish species that travel through or reside in park waters!

Sailing away to do further research! 
-Fio

Me measuring a Great Barracuda, it measured close to 100cm!
No Comments

Post A Comment