Presentation Abstract

For decades, biologists from the Seattle Aquarium have been informally monitoring bottom fish on rocky reefs in Neah Bay, Washington. Based on increasing concern over the long term stability of bottom fish populations in this area by both state and federal agencies, the Aquarium formalized monitoring in 2005 with diver-based video surveys to quantify bottom fish (rockfish and lingcod) diversity and abundance over time. Divers performed 100-meter video transects, devised to be non-invasive and repeatable, to assess diurnally active and relatively sessile bottom fishes over time. Transects were conducted in the Strait of Juan de Fuca each year in August from 2005-2013 at five permanently marked sites. Density and diversity of bottom fish species were determined by biologists counting fish via the archived video. Over the past nine years, there has been no significant difference in diversity and density of adult rockfish among sites or years, but there have been significant young of the year (YOY) rockfish recruitment events in 2006, 2008 and 2010, termed “jackpot recruitment events”. We also found that young of the year rockfish densities in the “jackpot” years were significantly correlated with lower sea surface temperatures. Rockfish recruitment may be generally poor because larval survival and settlement are dependent upon changing conditions such as climate, abundance of predators, oceanic currents, and chance events. Being long-lived allows the adult population to persist through many years of poor reproduction until a good recruitment year occurs, as in 2006, 2008 and 2010.This study may elucidate significant trends in rockfish diversity and abundance, that will influence long term management plans for rockfish conservation.

Session Title

Session S-10E: Evaluation, Conservation and Restoration of Species Associated with High-Relief, Rocky Habitat in the Salish Sea

Conference Track

Species and Food Webs

Conference Name

Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)

Document Type

Event

Start Date

2-5-2014 1:30 PM

End Date

2-5-2014 3:00 PM

Location

Room 613-614

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

Text

Language

English

Format

application/pdf

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May 2nd, 1:30 PM May 2nd, 3:00 PM

Nine years of rockfish surveys in the Strait of Juan de Fuca

Room 613-614

For decades, biologists from the Seattle Aquarium have been informally monitoring bottom fish on rocky reefs in Neah Bay, Washington. Based on increasing concern over the long term stability of bottom fish populations in this area by both state and federal agencies, the Aquarium formalized monitoring in 2005 with diver-based video surveys to quantify bottom fish (rockfish and lingcod) diversity and abundance over time. Divers performed 100-meter video transects, devised to be non-invasive and repeatable, to assess diurnally active and relatively sessile bottom fishes over time. Transects were conducted in the Strait of Juan de Fuca each year in August from 2005-2013 at five permanently marked sites. Density and diversity of bottom fish species were determined by biologists counting fish via the archived video. Over the past nine years, there has been no significant difference in diversity and density of adult rockfish among sites or years, but there have been significant young of the year (YOY) rockfish recruitment events in 2006, 2008 and 2010, termed “jackpot recruitment events”. We also found that young of the year rockfish densities in the “jackpot” years were significantly correlated with lower sea surface temperatures. Rockfish recruitment may be generally poor because larval survival and settlement are dependent upon changing conditions such as climate, abundance of predators, oceanic currents, and chance events. Being long-lived allows the adult population to persist through many years of poor reproduction until a good recruitment year occurs, as in 2006, 2008 and 2010.This study may elucidate significant trends in rockfish diversity and abundance, that will influence long term management plans for rockfish conservation.