Assessing vulnerability of fish spawning aggregations to fishing in the Gulf of Mexico

[mbjones]

Author: Brad Erisman Topics: fisheries

Summary of Synthesis

As part of the currently funded RESTORE Act project, my team was tasked with compiling existing biological and fisheries information for 30 species of marine fishes known or likely to form spawning aggregations. Similarly, we sought to identify existing monitoring programs in the region that could be modified in some way to also inform our study and regional monitoring of spawning aggregations and their fisheries. As a means for accomplishing these goals, our team has compiled a searchable online database of more than 900 references (peer-reviewed ms, reports, etc) that contain relevant biological and fisheries information relevant to the focal species, spawning behavior, and fishing patterns. Moreover, we have created several databases that summarizes a suite intrinsic biological parameters (e.g. life history parameters, behavioral parameters related to spawning aggregation dynamics) and extrinsic fisheries parameters (e.g. spatial regulations, gear restrictions, % catch from aggregations, etc) and which is completely cross-referenced with the online reference database. We have also used these data to construct spawning season tables for each species and estimate the interaction strength between fishing activities and spawning activities to identify which species are heavily targeted during spawning. All of the information has been compiled, vetted by an expert panel of 40 scientists, fishers, managers, and other stakeholders. Therefore, this massive set of information for a group synthesis project that seeks to take a innovative approach on the best analytical techniques for assessing the vulnerability of various aggregating species to fishing pressure in the Gulf as a means for prioritizing future research, assessment, and management efforts (see project objectives in previous statement).

[adellapa]

How would you measure vulnerability for these species? Also, are you interested in vulnerability for larvae or adult stages? I understand that you have already a large database filled with various information on these species biology and life history. But what exactly would be the objective of the study?

[demutsertlab]

Does this analysis span the entire Gulf of Mexico or are you focussing on a smaller area of the Gulf, and where?

[berisman]

We are using the compiled information to complete the following objectives: (1) Characterize the spatial, temporal, and behavioral patterns of spawning aggregations for the most important commercial and recreational species (e.g. groupers, snappers, croakers and drums). (2) Compare spatio-temporal dynamics of spawning aggregations with fishing activities (e.g. seasonal patterns of catch and cpue) to assess interaction strength and importance of aggregations to fisheries production.

(3) Assess the vulnerability of spawning aggregations to regional fisheries.

To measure vulnerability of a species to regional fishing activities requires an understanding of a suite of both intrinsic (biological, behavioral) and extrinsic (fishing behavior and efficiency, gears, regulations and protection measures in place) factors that will determine the degree to which fishing targets aggregations, how efficiently and rapidly they can harvest them, and how the species would respond to targeted fishing pressure. Therefore, we've compiled a long list of information on all these factors for each species. While it's not completely finished (but will be before July 1st), we've housed all the information on our project website, which is publicly available for viewing and downloading at:

[http://gcoos3.tamu.edu/restore/]

We are exploring how best to organize these parameters to generate some type of vulnerability matrix, and I'm hoping the workshop can serve to facilitate this process.

This project does span the entire Gulf and focuses specifically on the vulnerability of spawning aggregations as opposed to other life history stages (e.g. non-spawning adults or juveniles). It includes species that occupy offshore reefs, are commercially fished, and are federally managed to those that are inshore, exclusively targeted by recreational fishers, and managed by states.

[kfrasier]

This is an interesting proposal because the data have already been assembled and curated, so we could really focus on how to extract meaning from an aggregation of different datatypes. Since aggregated databases like this are increasingly common for the Gulf and other regions, it seems like a worthwhile exercise to spend time exploring ways to leverage them.