Evaluation of a Rubber-Compound Diaphragm for Acoustic Fisheries Surveys: Effects on Dual-Beam Signal Intensity and Beam Patterns

Fleischer, Guy W.; Argyle, Ray L.; Nester, Ralph.; Dawson, James J.

doi:10.1006/jsvi.2002.5139

Cited by 3 publications

(1 citation statement)

References 5 publications

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“…With the exception of one unit used in 2001, echosounders have been calibrated during the survey using methods described in Foote et al (1987) and MacLennan and Simmonds (1992). Transducer deployment techniques have included a towfish, sea chests (Fleischer et al 2002), hull mounting, and sonar tubes. While the towfish samples more of the water column than other methods, all methods lead to a portion of the upper water column (top 3-4 m) being unsampled.…”

Section: Fish Data Collection and Processingmentioning

confidence: 99%

Status of pelagic prey fishes in Lake Michigan, 2013

Warner¹,

Farha²,

O’Brien³

et al. 2014

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Acoustic surveys were conducted in late summer/early fall during the years 1992-1996 and 2001-2013 to estimate pelagic prey fish biomass in Lake Michigan. Midwater trawling during the surveys as well as target strength provided a measure of species and size composition of the fish community for use in scaling acoustic data and providing species-specific abundance estimates. The 2013 survey consisted of 27 acoustic transects (546 km total) and 31 midwater trawl tows. Mean prey fish biomass was 6.1 kg/ha (relative standard error, RSE = 11%) or 29.6 kilotonnes (kt = 1,000 metric tons), which was similar to the estimate in 2012 (31.1 kt) and 23.5% of the long-term (18 years) mean. The numeric density of the 2013 alewife year class was 6% of the time series average and this year-class contributed 4% of total alewife biomass (5.2 kg/ha, RSE = 12%). Alewife ≥age-1 comprised 96% of alewife biomass. In 2013, alewife comprised 86% of total prey fish biomass, while rainbow smelt and bloater were 4 and 10% of total biomass, respectively. Rainbow smelt biomass in 2013 (0.24 kg/ha, RSE = 17%) was essentially identical to the rainbow smelt biomass in 2012 and was 6% of the long term mean. Bloater biomass in 2013 was 0.6 kg/ha, only half the 2012 biomass, and 6% of the long term mean. Mean density of small bloater in 2013 (29 fish/ha, RSE = 29%) was lower than peak values observed in 2007-2009 and was 23% of the time series mean. In 2013, pelagic prey fish biomass in Lake Michigan was similar to Lake Huron, but pelagic community composition differs in the two lakes, with Lake Huron dominated by bloater. 1Presented at:Great Lakes Fishery Commission Lake Michigan Committee Meeting Windsor, ON, March 25-26, 2014 2 INTRODUCTIONAnnual evaluation of long-term data on prey fish dynamics is critical in light of changes to the Lake Michigan food web during the last 40 years (Madenjian et al. 2002) and continued restructuring due to exotic species, pollution, fishing, and fish stocking. Alewives are the primary prey in Lake Michigan and of especial importance to introduced salmonines in the Great Lakes (Elliott 1993;Rybicki and Clapp 1996;Warner et al. 2008;Jacobs et al. 2013), and, as such, constitute an important food web component. The traditional Great Lakes Science Center (GLSC) prey fish monitoring method (bottom trawl) is inadequate for fish located off bottom (Fabrizio et al. 1997). In particular, bottom trawls provide particularly biased estimates for age-0 alewives (Alosa pseudoharengus) based on catchability estimates from stock assessment modeling (Tsehaye et al. 2014). Much of the alewife biomass will not be recruited to bottom trawls until age-3 (Madenjian et al. 2005), but significant predation by salmonines may occur on alewives ≤ age-2 . Alewife abundance patterns tend to be highly variable because recruitment of alewife is variable and total alewife density is highly correlated with the density of alewife ≤ age-2 . Because of the ability of acoustic equipment to count organisms far above bottom, this type ...

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Section: Fish Data Collection and Processingmentioning

confidence: 99%

Status of pelagic prey fishes in Lake Michigan, 2013

Warner¹,

Farha²,

O’Brien³

et al. 2014

View full text Add to dashboard Cite

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The Lake Huron pelagic fish community: persistent spatial pattern along biomass and species composition gradients

Warner

Schaeffer

O’Brien

2009

Can. J. Fish. Aquat. Sci.

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Spatial patterns in the biomass of pelagic fish in Lake Huron have persisted over 10 years even though biomass decreased 86% and the fish community shifted from dominance by non-native species (rainbow smelt, Osmerus mordax ) to dominance by native species (bloater, Coregonus hoyi ). Based on multivariate analyses of acoustic biomass data and abiotic variables from the years 1997, 2004, 2005, and 2007, the strength of relationships between abiotic variables (primarily bottom depth) and fish community composition gradients decreased with fish biomass, suggesting that at high biomass, the influence of the measured abiotic variables is minimal. We observed consistently higher biomass in the North Channel and Georgian Bay than in the Main Basin, and as a result, we conclude that these smaller basins are likely important contributors to lakewide fish biomass, production, and dynamics. These results suggest that at current biomass levels, efforts to understand ecology, population dynamics, and lakewide abundance need to incorporate the effects of depth and geographic variation on fish distributions and ecology.

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The Influence of Alewife Year‐Class Strength on Prey Selection and Abundance of Age‐1 Chinook Salmon in Lake Michigan

et al. 2008

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We used growth and diet data from a fishery‐independent survey of Chinook salmon Oncorhynchus tshawytscha, acoustic estimates of prey density and biomass, and statistical catch‐at‐age modeling to study the influence of the year‐class strength of alewife Alosa pseudoharengus on the prey selection and abundance of age‐1 Chinook salmon in Lake Michigan during the years 1992‐1996 and 2001‐2005. Alewives age 2 or younger were a large part of age‐1 Chinook salmon diets but were not selectively fed upon by age‐1 Chinook salmon in most years. Feeding by age‐1 Chinook salmon on alewives age 2 or younger became selective as the biomass of alewives in that young age bracket increased, and age‐1 Chinook salmon also fed selectively on young bloaters Coregonus hoyi when bloater density was high. Selection of older alewives decreased at high densities of alewives age 2 or younger and, in some cases, high densities of bloater. The weight and condition of age‐1 Chinook salmon were not related to age‐1 Chinook salmon abundance or prey abundance, but the abundance of age‐1 Chinook salmon in year t was positively related to the density of age‐0 alewives in year t − 1. Our results suggest that alewife year‐class strength exerts a positive bottom‐up influence on age‐1 Chinook salmon abundance, prey switching behavior by young Chinook salmon contributing to the stability of the predator‐prey relationship between Chinook salmon and alewives.

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Evaluation of a Rubber-Compound Diaphragm for Acoustic Fisheries Surveys: Effects on Dual-Beam Signal Intensity and Beam Patterns

Cited by 3 publications

References 5 publications

Status of pelagic prey fishes in Lake Michigan, 2013

Status of pelagic prey fishes in Lake Michigan, 2013

The Lake Huron pelagic fish community: persistent spatial pattern along biomass and species composition gradients

The Influence of Alewife Year‐Class Strength on Prey Selection and Abundance of Age‐1 Chinook Salmon in Lake Michigan

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