Tailoring Ecological Monitoring to Individual Marine Reserves: Comparing Longline to Hook-and-Line Gear to Monitor Fish Species

Abstract

Fishery-independent hook-and-line surveys are currently being used to assess marine reserve performance in California and Oregon using a regionally standardized approach. Catch compositions generated from these hook-and-line surveys (pole-and-line gear) at Oregon’s southernmost marine reserve were compared with local commercial landing data. Several species present in the commercial catch were undersampled in the marine reserve hook-and-line dataset, including China Rockfish Sebastes nebulosus, Vermilion Rockfish S. miniatus, Quillback Rockfish S. maliger, Copper Rockfish S. caurinus, and Cabezon Scorpaenichthys marmoratus. We conducted a gear selectivity study to explore whether modified commercial long-lining gear could supplement current hook-and-line efforts. Both gear types were fished simultaneously from a single vessel inside and outside of the reserve. Species composition, catch rate, size distribution, and fish condition between the two gear types were compared. Catch composition differed significantly between longline and hook-and-line gear. Catch rates of nearshore rocky reef fish species were higher for longline than hook-and-line gear for all but two species. Importantly, higher catch rates were significant for three of the species of interest (Cabezon, Vermilion Rockfish, and Copper Rockfish). For four different species, larger individuals were caught on the longline compared with the hook-and-line gear. Incidence of predation and mortality were higher with long-lining but limited to three species groups: Black Rockfish S. melanops, Blue Rockfish S. mystinus and Deacon Rockfish S. diaconus complex, and Canary Rockfish S. pinniger. Symptoms of barotrauma were higher with hook-and-line gear. We demonstrated that longline gear can be used to catch and release species targeted by the local fishery and used simultaneously with hook-and-line gear from a single vessel to broaden both the species and the size ranges sampled. These results underscore the need to consider regionally standardized long-term monitoring approaches in conjunction with locally tailored efforts to generate data for detecting marine reserve effects at both local and regional scales.

Received September 20, 2016; accepted July 17, 2017

ACKNOWLEDGMENTS

Erin Jaco, Kelly Lawrence, Zachary Locklear, Scott Marion, and D. Wolfe Wagman contributed to at-sea data collection. Ted Calavan generously queried the commercial landing data for Port Orford collected by the ODFW. The authors gratefully acknowledge the participation, professionalism, and knowledge shared by Captain Jeff Miles of the FV Top Gun in conducting at-sea sampling and his contributions to the study design. We would also like to acknowledge the David and Lucile Packard Foundation and the Partnership for the Interdisciplinary Studies of Coastal Oceans for their funding of J.L.W.; this is the Partnership for the Interdisciplinary Studies of Coastal Oceans Contribution Number 461.