Modelling Fishing Gear to Address "More than Minimal and Not Temporary" Fishing Effects to Essential Fish Habitat

• Main Author: Nimick, Aileen Margaret
• Format: Thesis
• Language: English
• Published: Alaska Pacific University 2018
• Subjects: Aquatic sciences; Bering Sea; Pacific
• Online Access: http://pqdtopen.proquest.com/#viewpdf?dispub=10845718

The Magnuson-Stevens Fishery Conservation and Management Act (MSA; Magnuson-Stevens Fishery Conservation and Management Act. 2014. (16 U.S.C. 1801–1891(d)) mandates that fisheries management councils in the United States prevent adverse, or “more than minimal and not temporary”, fishing effects to essential fish habitat (EFH) to the extent practicable. Councils were left to decide what effects qualified as “minimal” and “temporary”. The lack of explicit definition in the MSA and its accompanying Final Rule has resulted in inconsistent habitat management throughout the country. The EFH mandate was written under an implicit assumption that councils have the scientific information necessary to effectively manage EFH. Basic information is lacking, such as what type of habitat occurs where, and how fishing effects habitat features. Chapter 1 briefly reviews the history of EFH regulation, the consequences of regulatory ambiguities and information gaps, and highlights that high latitude fisheries management can be disproportionately affected by climate variability. Thus, requiring investment in baseline habitat assessment and monitoring and renewed focus on under developed areas of research e.g. Fishing effects and gear-habitat interactions. Councils have attempting to quantitatively describe fishing effects to EFH through the use of mathematical models. The most recent of which, the Fishing Effects (FE) Model, was used in the North Pacific Fisheries Management Council 2015 EFH Review cycle. The FE Model uses discrete time steps (monthly) and spatially explicit fishing effort and sediment data to calculate an estimated habitat disturbance. The FE Model is calculated in two-dimensions and implicitly assumes that if fishing gear does not contact the seabed, then there is no gear-habitat interaction. Some features stand taller than raised gear (e.g. sea whips, Halipteris willemoesi, in the North Pacific can up to 2m tall) and may interact with fishing gear. The FE Model in two-dimensions does not account for this potential interaction and cannot effectively simulate gear modifications. Chapter 2 proposes an adapted version of the FE Model that accounts for the vertical interactions through the use of discrete height bins. To accurately estimate interactions on and above the seabed, fishing gear has to be recharacterized. To demonstrate this the Bering Sea flatfish trawl was recharacterized by calculating how much of the nominal gear width is present in each height bin. A detailed methodology is provided to allow this method to be applied to any fishing gear. The adapted FE Model can be used to simulate gear modifications, as is shown by simulating two modifications of the flatfish trawl. This chapter will inform the 2020 EFH Review cycle as the FE Model is improved.