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Two sides of the same coin – fisheries science and management

Published on Thursday, February 4, 2021

Two sides of the same coin – fisheries science and management

By: Bryan Keller,
Knauss Fellow,
Foreign Affairs Fellow,
NOAA Fisheries Office of International Affairs and Seafood Inspection

 

There are plenty of fish in the sea and some of them taste really good. That is how the saying goes, right? Fisheries management is the reason why plenty of fish continue to be in the sea. This field ensures (or attempts to ensure) that populations of fishes remain healthy so that global citizens can continue benefiting from consuming fisheries products. But, without fisheries science, the research that advances our understanding of the field, fisheries management would not be successful. Transitioning from the world of academia to the world of policy, through my Knauss Fellowship, I saw the important connection between these two fields first-hand.

 

Throughout graduate school, I participated in research focused on improving fisheries management. This science involves replicating commercial fishing activities under controlled settings to better understand the ecological effects of such activities.  A very common method of commercial fishing used to obtain fisheries products is called “longlining”. What is a longline, you might ask? Well…it’s a very long line, sometimes tens of miles long with thousands of evenly spaced fishing hooks. It takes fishers many hours to deploy this gear in the water where it then soaks for many more. The gear is then retrieved and the catch is hauled. 

 

Longline fisheries have specific focus species that are targeted, such as tunas or swordfish, but other species are often caught as well – this is called bycatch. There are a few major concerns regarding bycatch, including 1) given the long soak times, many animals are dead when the gear is hauled, 2) animals released alive may die due to the stress of capture and 3) many bycatch species have conservative life history characteristics and are therefore susceptible to overfishing or population depletion. Due to these circumstances, reducing bycatch mortality is one of the most complex issues in fisheries management. From a scientific standpoint, it makes sense to try and mitigate bycatch mortality so the species’ population remains healthy. Bycatch mortality is typically divided into two categories: animals that die while on the hook and those that die after being released (post-release mortality). 

 

Image
A great hammerhead in Bimini, Bahamas (photo credit Annie Guttridge).

 

My graduate school advisor, Dr. Dean Grubbs, led multiple projects focused on reducing the bycatch mortality of sharks and I was lucky enough to assist with that research. My favorite project focused on hammerheads, specifically great and scalloped hammerheads. Our goal was to quantify the post-release mortality of hammerheads after being released from a commercial fishing vessel and to better understand what factors contributed to this mortality. In order to do this, we deployed fishing gear that replicated commercial longlines. On each fishing hook, we added a “hook timer” so we could know how long an animal had been on the hook. We also analyzed a blood sample from each shark when we caught them. Before we released the shark, we attached a satellite tag on the animal. This tag allowed us to determine if the shark had died after it was released. Using the amount of time the animal was on the hook and stress physiology parameters from the blood analysis, we could determine how the time on hook affected the shark’s stress and mortality levels. My subsequent fellowship experience helped me better understand how such data could make a difference in fisheries management. 

 

Throughout my Knauss Fellowship, I have spent a significant amount of time representing NOAA Fisheries through my work relevant to the International Commission for the  Conservation of Atlantic Tunas (ICCAT). ICCAT is a Regional Fisheries Management Organization, with over 50 countries involved in the Commission. The geographic scope of ICCAT is the entire Atlantic Ocean, so any country that fishes for ICCAT-managed species, such as tunas or swordfish, is meant to follow the management measures put forth by the Commission. 

 

Image
Bryan Keller secures a great hammerhead shark during a fishery-independent survey in Jupiter, FL (photo credit: Jojo Fraser).

Reducing bycatch mortality is a major focus of NOAA Fisheries and ICCAT. One such issue that I focused on was the bycatch mortality of the North Atlantic Shortfin mako shark. This stock is in quite a poor state (overfished with overfishing still occurring) so reducing the total mortality of the species is imperative and mitigating bycatch is one way to achieve that goal. The United States has done an incredible job reducing the mortality of this species in our own waters by implementing a number of requirements for U.S. fishers, including the use of circle hooks. These are specially shaped hooks that result in less gut- and foul-hooking, thereby reducing injury and related mortality. 

 

During my fellowship, I conducted a review, alongside Dr. Yonat Swimmer and Dr. Craig Brown, of the available literature on the effect of circle hooks on the North Atlantic shortfin mako. We produced a working paper and I presented it at an ICCAT meeting in May. Our paper resulted in the Sub-Committee on Ecosystems stating that circle hooks are effective for increasing at-haulback survival of the shortfin mako. This finding was relayed to ICCAT, where managers may use the information as a basis for developing new conservation strategies focused on reducing the bycatch mortality of the shortfin mako. 

 

My Knauss fellowship has truly highlighted the interdependence of fisheries management and fisheries science – one cannot function without the other. Both the research on hammerheads from graduate school and the science I reviewed on the shortfin mako were critical in better understanding the ecology of each species. Without scientific analysis of specific research questions, fisheries managers will not be able to make informed decisions to help conserve species. And without fisheries managers, the data and findings of scientists will have little to no conservation effect because there would be no way to implement their suggested management measures. 

 

While working solely in one field, fisheries science or fisheries management, it is not always obvious how the two come together. I’m grateful for my experiences on both sides of the fisheries “coin” and look forward to bringing what I’ve learned to my future endeavors in fisheries.

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