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At least 1,171 records · Page 65Linked to original sources

USGS2011

Long-term trends in habitat use of offshore demersal fishes in western Lake Huron suggest large-scale ecosystem change

We estimated mean depths of capture for offshore demersal fish species, grouped into three habitat-based guilds (shallow benthic, pelagic, and deep benthic), using fall bottom trawl data (27–73 m) in the western main basin of Lake Huron from 1976 to 2007. The mean depth of capture of the shallow and deep benthic guilds initially exhibited a trend toward capture in shallower water, switched to a trend toward capture in deeper water in 1991, and changed back to a trend toward capture in shallower water in 2001–2002. Species in the pelagic guild showed a similar pattern, but the initial change point occurred in 1981 for this guild. Individual species in these guilds showed variable patterns of depth distribution, but a feature common to all guilds and all pelagic and deep benthic species was a change to a trend toward capturing fish in shallower water that occurred nearly simultaneously (1999–2002). These common trends suggest that large-scale factors are affecting the habitat use of offshore demersal fish species in Lake Huron. The depth distributions of the three guilds have converged in recent years, indicating that the locations of suitable habitat for offshore demersal fishes may be changing. Our results indicate that the benthic ecology of the western main basin of Lake Huron is undergoing profound changes across a large spatial scale that are affecting the habitat use of offshore demersal fishes. We suggest that these changes are related to recent invasions of exotic species.

Lake Huron↗

USGS2021

Loop-mediated isothermal amplification (LAMP) assay for detection of Asian fish tapeworm, Schyzocotyle acheilognathi (Yamaguti, 1934) [syn. Bothriocephalus acheilognathi]

The Asian fish tapeworm ( Schyzocotyle acheilognathi syn. Bothriocephalus acheilognathi ) (AFT) is an invasive parasite that can infect many species of fish, although most hosts are primarily members of Cyprinidae. Pathogenicity has most often been reported in aquaculture settings in fry and fingerling stages of carp ( Cyprinus spp.). More recently, it has been shown to cause growth retardation in the endangered bonytail chub ( Gila elegans ) and found to be widespread in populations of endangered humpback chub ( Gila cypha ) in the Colorado River, Grand Canyon, Arizona. AFT spreads most often through the transport of infected fish, particularly baitfish. Despite its harmful potential, there is no efficient or accurate ante mortem test to detect AFT in water or fish samples before transport. Herein, we report on the development of a sensitive and specific loop-mediated isothermal amplification (LAMP) assay to detect the parasite in under 30 min from laboratory prepared samples. Six LAMP primers were designed to amplify a variable region of the 18S ribosomal RNA gene in AFT with the detection and quantification of DNA on a real-time fluorometer. The limit of detection was 1 × 10 1 copies/µl of DNA extracted from as few as 2 AFT eggs. Future application of our assay would be a low-cost test to rapidly and accurately detect AFT DNA from environmental samples on-site so that preventive actions can be taken to halt the spread of the AFT through the movement of infected fish.

Journal of Parasitology↗

USGS2009

Influence of small impoundments on habitat and fish communities in headwater streams

We surveyed the habitat and fish assemblages of four impounded and three unimpounded neighboring headwater streams, separated longitudinally into multiple upstream and downstream reaches. Instream habitat characteristics were similar between reaches of unimpounded streams and reaches above impoundments, and differed significantly from reaches below impoundments that included deeper water and more stable flows. Species richness was similar above and below impoundments, and between impounded and unimpounded streams, but fish assemblage composition and structure differed. Stream reaches above impoundments supported higher percentages of centrarchids compared to upper reaches of unimpounded streams, which had more obligate stream cyprinids. Reaches below impoundments supported mainly centrarchid species whereas lower reaches of unimpounded streams supported a balanced mix of cyprinids and centrarchids. Percina maculata (Blackside Darter) occurred throughout the study area except in upper reaches of impounded streams, illustrating how stream fragmentation can lead to localized extirpations. Changes to the fish assemblages in reaches above impoundments were due to the loss of downstream connectivity, and changes to the fish assemblages below impoundments were due to alterations of instream habitat caused by the impoundments. Small impoundments can have important effects on fish faunas of small geographical areas, but also potentially large cumulative effects if distribution of impoundments is not administered strategically at the scale of the river basin. We caution that continual population increase, recent droughts, and projected changes in climate patterns are prompting a renewed interest in impoundment construction, and urge close regulatory oversight over such projects.

Southeastern Naturalist↗

USGS2004

Correlations among densities of stream fishes in the upper Neosho River, with focus on the federally threatened Neosho madtom Noturus placidus

We sampled fishes monthly from November 2000 to October 2001 at four gravel bar sites along a 34-km stretch of the upper Neosho River in Lyon County, Kansas. We assessed the potential for interspecific competition among stream fishes, with focus on the federally threatened Neosho madtom, Noturus placidus , by using Pearson's correlation analysis with sequential Bonferroni correction of alpha to examine relationships among fish densities. Of the 19 fish species analyzed, there were six significant positive and no significant negative correlations. Abundance of N. placidus did not vary significantly with total abundance of fishes or with abundance of any of these potential competitors. The lack of significant negative correlations at these sites at this time might reflect an assemblage in equilibrium or one controlled abiotically rather than by ongoing active competition.

Transactions of the Kansas Academy of Science↗

USGS2004

Influential environmental gradients and spatiotemporal patterns of fish assemblages in the unimpounded Upper Mississippi River

We investigated variation of fish assemblages in response to environmental factors using Long Term Resource Monitoring Program data. Data were collected from 1993 to 2000 from five physical habitats in the unimpounded upper Mississippi River. We captured 89 species composing 18 families. Of these, 26% were fluvial specialists, 25% were fluvial dependent and 49% were generalists. The numerically dominant component of the adult fish assemblage (species accounting for >10% of total catch) accounted for 50% of the assemblage and was comprised of only three species: gizzard shad ( Dorosoma cepedianum ; 25%), common carp ( Cyprinus carpio , 15%) and channel catfish ( Ictalurus punctatus , 10%). The dominant component of the YOY fish assemblage was comprised of only two species, which accounted for 76% of the total catch: freshwater drum ( Aplodinotus grunniens ; 39%) and gizzard shad (37%). We used a cross-validation multivariate approach to explore how adult and young-of-the-year (YOY) assemblages varied with respect. to physical habitat and environmental gradients. Furthermore, we were interested how the fish assemblages changed over time. Partial canonical correspondence analyses (pCCA) demonstrated significant effects of physical habitats. Such effects differed between young-of-the-year and adult fishes. The four main environmental gradients influencing overall assemblage structure for both age groups were river elevation, water velocity, conductivity, and depth of gear deployment. Morisita's index revealed similar adult assemblage structure over time. However, the YOY assemblage present in 1995 was dissimilar from assemblages present during the other years. We speculate this is a lag effect from the backwater spawning episodes (floodpulse) that occurred with the 500-y flood in 1993. Shannon-Weiner diversity and Camargo's evenness indices were low, but stable across years for the adult assemblage, but varied across years for the YOY assemblage.

Illinois, Kentucky, Missouri↗

USGS2012

Optimum swimming pathways of fish spawning migrations in rivers

Fishes that swim upstream in rivers to spawn must navigate complex fluvial velocity fields to arrive at their ultimate locations. One hypothesis with substantial implications is that fish traverse pathways that minimize their energy expenditure during migration. Here we present the methodological and theoretical developments necessary to test this and similar hypotheses. First, a cost function is derived for upstream migration that relates work done by a fish to swimming drag. The energetic cost scales with the cube of a fish's relative velocity integrated along its path. By normalizing to the energy requirements of holding a position in the slowest waters at the path's origin, a cost function is derived that depends only on the physical environment and not on specifics of individual fish. Then, as an example, we demonstrate the analysis of a migration pathway of a telemetrically tracked pallid sturgeon ( Scaphirhynchus albus ) in the Missouri River (USA). The actual pathway cost is lower than 10 5 random paths through the surveyed reach and is consistent with the optimization hypothesis. The implication—subject to more extensive validation—is that reproductive success in managed rivers could be increased through manipulation of reservoir releases or channel morphology to increase abundance of lower-cost migration pathways.

Missouri River↗

USGS2014

Nearshore energy subsidies support Lake Michigan fishes and invertebrates following major changes in food web structure

Aquatic food webs that incorporate multiple energy channels (e.g. nearshore benthic or pelagic) with varying productivity and turnover rates convey stability to biological communities by providing multiple independent energy sources. Within the Lake Michigan food web, invasive dreissenid mussels have caused rapid changes to food web structure and potentially altered the channels through which consumers acquire energy. We used stable C and N isotopes to determine how Lake Michigan food web structure has changed in the past decade, coincident with the expansion of dreissenid mussels, decreased pelagic phytoplankton production and increased nearshore benthic algal production. Fish and invertebrate samples collected from sites around Lake Michigan were analyzed to determine taxa-specific 13C:12C (delta 13C) and 15N:14N (delta 15N) ratios. Sampling took place during two distinct periods, 2002-2003 and 2010-2012, that spanned the period of dreissenid expansion, and included nearshore, pelagic and profundal fish and invertebrate taxa. Magnitude and direction of the 13C shift indicated significantly greater reliance upon nearshore benthic energy sources among nearly all fish taxa as well as profundal invertebrates. Although the mechanisms underlying this 13C shift likely varied among species, possible causes include the transport of benthic algal production to offshore waters and an increased reliance on nearshore prey items. Delta 15N shifts were more variable and of smaller magnitude across taxa although declines in delta 15N among some pelagic fishes may indicate a shift to alternative prey resources. Lake Michigan fishes and invertebrates appear to have responded to dreissenid induced changes in nutrient and energy pathways by switching from pelagic to alternative nearshore energy subsidies. Although large shifts in energy allocation (i.e. pelagic to nearshore benthic) resulting from invasive species appear to have affected total production at upper trophic levels, changes in trophic structure and utilization of novel energy pathways may help to stabilize food webs following species invasions.

Lake Michigan↗

USGS2009

Trophic relationships of small nonnative fishes in a natural creek and several agricultural drains flowing into the Salton Sea, and their potential, effects on the endangered desert pupfish

This study was conducted to characterize trophic relationships of small nonnative fishes and to determine if predation by these fishes contributes to the decline of desert pupfish (Cyprinodon macularius), an endangered cyprinodont on the verge of extinction. We sampled 403 hybrid Mozambique tilapias (Oreochromis mossambica by O. urolepis), 107 redbelly tilapias (Tilapia zillii), 32 longjaw mudsuckers (Gillkhthys mirabilis), 182 western mosquitofish (Gambusia affinis), 222 sailfin mollies (Poecilia latipinna), 63 shortfin mollies (Poecilia mexicana), and 235 porthole livebearers (Poecilurpsis gracilis) from a natural creek and four agricultural drains during September 1999- December 2001. Evidence of piscivory was in gastrointestinal contents of 14 hybrid Mozambique tilapias, 3 redbelly tilapias, 10 longjaw mudsuckers, 8 western mosquitofish, 2 sailfin mollies, and 8 porthole livebearers. Although digestion often was too advanced for identification of fishes consumed by nonnative fishes, remains of desert pupfish were in gastrointestinal contents of a longjaw mudsucker. Our findings, along with Field evidence from other studies that inverse relationships exist between abundances of desert pupfish and nonnative species, are consistent with the hypothesis that predation by nonnative species is contributing to decline of desert pupfish. We suspect that competitive interactions with nonnative fishes might also adversely affect abundance of desert pupfish.

Southwestern Naturalist↗

USGS2006

Dietary exposure of mink (Mustela vison) to fish from the Housatonic River, Berkshire County, Massachusetts, USA: Effects on organ weights and histology and hepatic concentrations of polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalence

The effects of feeding ranch mink ( Mustela vison ) diets containing polychlorinated biphenyl (PCB)-contaminated fish (88 gold fish [ Carassius auratus ] weighing a total of 70.3 kg and 16 carp [ Cyprinus carpio ] weighing a total of 77.3 kg) collected from the Housatonic River (HR; Berkshire County, MA, USA) in October 1999 on organ weights and histology and hepatic concentrations of total PCBs (ΣPCBs) and 2,3,7,8-tetrachlorodibenzo- p -dioxin toxic equivalence (TEQ) were evaluated. Diets contained 0.22 to 3.54% HR fish, which provided 0.34 to 3.7 μg ΣPCBs/g feed (3.5-69 pg TEQ/g feed). Female mink were fed the diets eight weeks before breeding through weaning of kits at six weeks of age. Offspring were maintained on their respective diets for an additional 180 d. The dietary concentration of PCBs that caused a decrease in kit survival (3.7 μg ΣPCBs/g feed [69 pg TEQ/g]) resulted in a maternal hepatic concentration of 3.1 μg ΣPCBs/g wet weight (218 pg TEQ/g). Organ weights were not consistently affected. Mandibular and maxillary squamous cell proliferation was apparent in 31-week-old juveniles exposed to as low as 0.96 (xg ΣPCBs/g feed (9.2 pg TEQ/g). Juveniles in this treatment group had a liver concentration of 1.7 μg ΣPCBs/g wet weight (40 pg TEQ/g). Because inclusion of PCB-contaminated fish, which comprised approximately 1% of the diet, resulted in mandibular and maxillary squamous cell proliferation, it is possible that consumption of up to 30-fold that quantity of HR fish, as could be expected for wild mink, would result in more severe lesions characterized by loss of teeth, thus impacting survivability.

Environmental Toxicology and Chemistry↗

USGS2006

Use of the oligochaete, Lumbriculus variegatus, as a prey organism for toxicant exposure of fish through the diet

The oligochaete, Lumbriculus variegatus, has several characteristics that make it desirable as a prey organism for conducting dietary exposure studies with fish. We conducted 21- and 30-d experiments with young fathead minnows (Pimephales promelas) and rainbow trout (Oncorhynchus mykiss), respectively, to determine whether a diet consisting solely of L. variegatus would support normal growth and to compare performance with standard diets (Artemia nauplii, frozen brine shrimp, or trout chow). All diets were readily accepted, and fish survived and grew well. Food conversion in both fathead minnows and rainbow trout was as high as or higher for the oligochaete diet compared with others, although this comparison is influenced by differences in ration, ingestion rate, or both. The oligochaete diet had gross nutritional analysis similar to the other diets, and meets fish nutrition guidelines for protein and essential amino acids. Methodologies and practical considerations for successfully using oligochaetes as an experimental diet are discussed. Considering their ready acceptance by fish, their apparent nutritional sufficiency, the ease of culturing large numbers, and the ease with which they can be loaded with exogenous chemicals, we believe that L. variegatus represents an excellent choice of exposure vector for exposing fish to toxicants via the diet. ?? 2006 SETAC.

Environmental Toxicology and Chemistry↗

USGS2009

Organochlorine contaminants in fishes from coastal waters west of Amukta Pass, Aleutian Islands, Alaska, USA

Organochlorines were examined in liver and stable isotopes in muscle of fishes from the western Aleutian Islands, Alaska, in relation to islands or locations affected by military occupation. Pacific cod (Gadus macrocephalus) , Pacific halibut (Hippoglossus stenolepis) , and rock greenling (Hexagrammos lagocephalus) were collected from nearshore waters at contemporary (decommissioned) and historical (World War II) military locations, as well as at reference locations. Total (Σ) polychlorinated biphenyls (PCBs) dominated the suite of organochlorine groups (ΣDDTs, Σchlordane cyclodienes, Σother cyclodienes, and Σchlorinated benzenes and cyclohexanes) detected in fishes at all locations, followed by ΣDDTs and Σchlordanes; dichlorodiphenyldi-chloroethylene ( p , p ′DDE) composed 52 to 66% of ΣDDTs by species. Organochlorine concentrations were higher or similar in cod compared to halibut and lowest in greenling; they were among the highest for fishes in Arctic or near Arctic waters. Organochlorine group concentrations varied among species and locations, but ΣPCB concentrations in all species were consistently higher at military locations than at reference locations. Moreover, all organochlorine group concentrations were higher in halibut from military locations than those from reference locations. A wide range of molecular weight organochlorines was detected at all locations, which implied regional or long-range transport and deposition, as well as local point-source contamination. Furthermore, a preponderance of higher-chlorinated PCB congeners in fishes from contemporary military islands implied recent exposure. Concentrations in all organochlorine groups increased with δ 15 N enrichment in fishes, and analyses of residual variation provided further evidence of different sources of ΣPCBs and p , p ′DDE among species and locations.

Alaska↗

USGS2021

Fish habitat use and food web structure following pond and plug restoration of a Montane Meadow in the Sierra Nevada, California

Montane meadows are areas of high biodiversity and provide many important ecosystem services; however, degradation of 40–60% of these habitats in the Sierra Nevada region of California has left many of these areas impaired. The “pond-and-plug” meadow-restoration technique is 1 type of treatment implemented to restore montane meadows. The objectives of this technique are to re-water the meadow and promote downstream flow by increasing the water-table elevation and providing additional water storage that will promote the growth of mesic and hydric vegetation that maintains and stabilizes stream channels. However, aquatic habitat and the composition and functioning of aquatic communities in these systems post-treatment are poorly documented or understood. We evaluated: (1) fish habitat, community composition, and relative abundance among recently created ponds spanning the range of pond habitats; (2) seasonal movement and survival of fish within and among ponds; and (3) food web structure in ponds. We documented over-summer and winter survival in the fish community and short-distance movement by 1 species occupying the ponds. Mark-recapture data suggest that all fish species present are capable of surviving both summer and winter conditions when pond conditions could be most limiting. Food web structure among intensively sampled ponds was similar, with overlapping isotopic niche width for dominant taxa. However, basal resource diversity (BRD) varied among ponds, with those having higher macrophyte cover also showing greater BRD. Our findings suggest that pond-and-plug techniques can provide habitat for native fishes that are able to tolerate departures from the species thermal and dissolved oxygen optima. Future meadow treatments could benefit from short-term restoration techniques such as pond-and-plug to allow for longer-term processes to influence meadow condition over time.

California↗

USGS2026

Field evaluation of the Automated Barge Clearing Deterrent (ABCD): Hydrodynamic, navigation, and fish response effects

The escape and subsequent spread of invasive carp (notably, bighead carp [ Hypophthalmichthys nobilis ] and silver carp [ H. molitrix ]) from aquaculture ponds and sewage lagoons into the Mississippi and Illinois Rivers poses a significant risk to further spread of these fish into the Great Lakes. Prior research demonstrated that commercial tows can transport juvenile invasive carp through locks and other barriers to fish migration. A recent physical model study recommended a linear array of bubble diffusers, the Automated Barge Clearing Deterrent (ABCD), for further evaluation in mitigating the transport of small fish in commercial tows. The present field study evaluated the ABCD for navigation safety and barge junction flushing capacity. An instrumented commercial tow executed 119 lock approaches with the ABCD both operating and idle. Pilot interviews and tow trajectory analysis indicated no significant navigation safety issues. The measured velocity data, fish recapture data, and a simple fish displacement model indicated that the ABCD produced sufficient flow to expel all passive objects and many small juvenile invasive carp. However, the ABCD is less likely to expel large juvenile invasive carp due to their stronger swimming ability. The ABCD and two alternative configurations prove strong contenders for further development and application.

Illinois↗

USGS1995

Waterbird predation on fish in western Lake Erie: a bioenergetics model application

To better understand the role of piscivorous waterbirds in the food web of western Lake Erie, we applied a bioenergetics model to determine their total fish consumption, The important nesting species included the Herring Gull (Larus argentatus), Ring-billed Gull (L. delawarensis), Double-crested Cormorant (Phalacrocorax auritus), Great Blue Heron (Ardea herodias), Black-crowned Night-Heron (Nycticorax nycticorax), and Great Egret (Casmerodius albus). The impact of migrant waterbirds, including the Red-breasted Merganser (Mergus serrator), on western Lake Erie fish biomass was also considered in the analysis. According to the modeling results, during the early 1990s, piscivorous waterbirds consumed 13,368 tonnes of fish from western Lake Erie each year. This tonnage was equivalent to 15.2% of the prey fish biomass needed to support the walleye (Stizostedion vitreum) population in western Lake Erie during a single growing season. The model application was useful in quantifying energy flow between birds and fish in a large lake ecosystem.

Condor↗

USGS1962

Fish kill from underwater explosions

The U.S. Geological Survey has used 23 different shotpoints during two seasons of field work in our seismic study of crustal structure in western United States. Without exception, it has been found that under-water shotpoints result in a more efficient conversion of explosive energy into seismic energy than do drilled-hole shotpoints. This experience, together with elimination of drilling costs, has led to the use of underwater shotpoints wherever possible. Three of the 23 shotpoints were in the Pacific Ocean, and for these we have no detailed information on the fish kill. Another six shotpoints were located in inland bodies of water. These are: * Soda Lake near Fallon, Nevada * Mono Lake near Lee Vining, California * Lake Mead near Boulder City, Nevada * Shasta Lake near Redding, California * C.J. Strike Reservoir near Bruneau, Idaho * Lucky Peak Reservoir near Boise, Idaho The 22 high-explosive charges, weighing a total of 95,100 pounds, that were fired in lakes containing fish life resulted in the known death of 2,413 game fish with a total weight of 759 pounds. The average mortality was 110 game fish or 34.5 pounds of game fish killed per average shot of 4,325 pounds of high-explosives.

California;Nevada;Idaho↗

USGS2014

Status of pelagic prey fishes in Lake Michigan, 2013

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.

Lake Michigan↗

USGS2004

Summary of total mercury concentrations in fillets of selected sport fishes collected during 2000-2003 from Lake Natoma, Sacramento County, California

This report summarizes results of total mercury measurements in skinless fillets of sport fishes collected during August 2000, September?October 2002, and July 2003 from Lake Natoma, a small (8,760 acre-feet) afterbay for Folsom Dam on the lower American River. The primary objective of the study was to determine if mercury concentrations in fillets approached or exceeded guidelines for human consumption. The Food and Drug Administration (FDA) human-health action level for methylmercury in commercially caught fish is 1.0 ?g/g (microgram per gram); the U.S. Environmental Protection Agency (USEPA) human-health criterion for methylmercury residue in fish tissue is 0.30 ?g/g. Wet weight concentrations of total mercury in skinless fillets were as high as 0.19 ?g/g in bluegill (Lepomis macrochirus), 0.39 ?g/g in redear sunfish (L. microlophus), 1.02 ?g/g in largemouth bass (Micropterus salmoides), and 1.89 ?g/g in channel catfish (Ictalurus punctatus). Maximum concentrations of mercury in other fish species varied from 0.10 ?g/g in rainbow trout (Oncorhynchus mykiss) to 0.56 ?g/g in white catfish (A-meiurus catus). Altogether, 1 of 86 largemouth bass and 11 of 11 channel catfish exceeded the FDA human-health action level. In addition, 1 of 20 redear sunfish, 26 of 86 largemouth bass, 2 of 3 spotted bass (M. punctulatus), 1 of 1 brown bullhead (A. nebulosus), and 1 of 1 white catfish exceeded the USEPA human-health criterion. These results indicate that some fish species inhabiting Lake Natoma contain undesirably high concentrations of mercury in their skinless fillets.

Data Series↗

USGS2020

Fish assemblages in eelgrass beds of Bellingham Bay, Washington, Northern Puget Sound, 2019

Puget Sound is a critical part of the Pacific Northwest, both culturally and economically. Eelgrass beds are an important feature of Puget Sound and are known to influence fish assemblages. As part of a larger site-characterization effort, and to gain a better understanding of the fish assemblages in Bellingham Bay, Washington, four eelgrass beds ( Zostera marina ) along the shoreline were surveyed. Fish were captured from 24 through 26 September 2019 by using three beach-seine hauls per eelgrass bed. In total, 12 hauls yielded 2,135 fish that comprised 20 species from 14 families. Shiner perch ( Cymatogaster aggregata ) accounted for 52 percent of the total catch. The other common species included three-spine stickleback ( Gasterosteus aculeatus ), bay pipefish ( Syngnathus leptorhynchus ), saddleback gunnel ( Pholis ornata ), Pacific staghorn sculpin ( Leptocottus armatus ), and Pacific sand lance ( Ammodytes personatus ). Total catch and species richness were highest at the two locations closest to the urban center of Bellingham; however, species diversity and evenness were highest at the two eelgrass beds farthest from the city center. Descriptions of fish assemblages in eelgrass beds are expected to be useful in the development of future process-based investigations by study partners and will focus on the movements of sediments and contaminants and their influence on biota.

Washington↗