929 resultados para habitats
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This is the Rivers Avon & Erme Salmon Action Plan Final document produced by the Environment Agency in 2004. The Rivers Avon and Erme Salmon Action Plan (SAP) has been produced after consideration of feedback from public consultation. The final plan provides a list of the agreed issues and actions for the next five years to maintain and improve the salmon stocks and fisheries of both rivers. Efforts have been made to identify possible sources of funding, partners and timescales. It indicates how the plan will be managed, including the process for reviewing stock status, issues, actions and progress. Low marine survival is currently a major factor limiting the numbers of salmon returning to spawn in both the Avon and the Erme. Actions to improve the accessibility of spawning areas and to maximise the productivity of spawning and nursery habitats are seen as priorities, which should help to offset the low marine survival. The quality of the information available to assess salmon stocks is recognised as a limiting factor in the management of salmon fisheries. The SAP aims also to promote long term collaboration between the Agency and other interested parties in managing the salmon stocks and fisheries of the Avon and the Erme.
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This is the River Dart Salmon Action Plan Consultation document produced by the Environment Agency in 2003. The report pays attention on the external consultation of the River Dart Salmon Action Plan (SAP). This strategy represents an entirely new approach to salmon management within the UK and introduces the concept of river-specific salmon spawning targets as a salmon management tool. The north of the River Dart catchment is included in the Dartmoor candidate Special Area of Conservation (cSAC), designated under the Council EC Directive 92/43/EEC, the “Habitats Directive”. One of the conservation objectives for the cSAC is to maintain the habitat for Atlantic Salmon, Salmo Salar in favourable condition. The River Dart is an important salmon, sea trout and brown trout fishery with no significant coarse fishery. However, eels are ubiquitous throughout the catchment and are lightly exploited. The River Dart SAP contains a description of the river catchment and highlights particular features that are relevant to the salmon population and the associated fishery.
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ABSTRACT TRANSCRIBED FROM ENGLE'S PH.D. ORAL DEFENSE PAMPHLET: The natural history of juvenile California spiny lobster, Panulirus interruptus (Randall), was investigated, with primary emphasis placed on ascertaining juvenile habitats, determining juvenile growth rates and component growth processes, and evaluating ecological and behavioral phenomena associated with juvenile survival and growth. Habitat surveys of island and mainland localities throughout southern and lower California revealed that small, greenish juveniles typically inhabit crevices or temporary burrows in 0-4m deep, wave-swept rocky habitats covered by dense beds of surf grass, Phyllospadix torreyi S. Watson. Phyllospadix beds were more abundant on gradually sloping rocky mainland beaches than on steeply sloping island shores. Phyllospadix abundance was positively correlated with P. interruptus abundance; however, at Santa Catalina Island, the Phyllospadix habitat was not extensive enough to be the sole lobster nursery. In laboratory tests, puerulus larvae and early juveniles chose Phyllospadix over rubble rocks or broad-bladed kelp, but did not consistently prefer Phyllospadix over reticulate algae. Ecology, growth, and behavior of juvenile P. interruptus inhabiting a discrete Phyllospadix habitat at Bird Rock, Santa Catalina Island, were investigated from October 1974 through December 1976 by means of frequent scuba surveys. Pueruli settled from June to November. Peak recruitment occurred from July to September, when seasonal temperatures were maximal. Settled larvae were approximately one year old. Juvenile growth was determined by size-frequency, single molt increment, mark-recapture, and laboratory culture studies. Carapace length vs. wet weight relationships fit standard power curve equations. Bird Rock juveniles grew from 7 to 32mm CL in 10-11 molts and from 32 to 56mm CL in 5-6 molts during their first and second benthic years, respectively. Growth rates were similar for males and females. Juveniles regenerating more than two limbs grew less per molt than intact lobsters. Long-term growth of laboratory-reared juveniles was 20% less than that of field lobsters. Growth component multiple regression analyses demonstrated that molt increment was directly proportional to premolt size and temperature for age 1+ lobsters. Molt frequency was inversely proportional to size and directly proportional to temperature. Temperature affected age 2+ lobsters similarly, but molt increment was independent of size, and molt frequency declined at a different rate. Juvenile growth rates more than doubled during warm water months compared to cold water months, primarily because of increased molt frequency. Based on results from this study and from previous investigations, it is estimated that P. interruptus males and females become sexually mature by ages 4 and 5 years, respectively, and that legai size is reached by 7 or 8 years of age. Juvenile P. interruptus activity patterns and foraging behavior were similar to those of adults, except that juvenile home ranges were proportionally smaller, and small juveniles were apparently not attracted to distant food. Small mollusks, abundant in Phyllospadix habitats, were the major food items. Size-dependent predation by fish and octopus apparently caused the considerable juvenile mortality observed at Bird Rock. Juveniles approaching 2 years of age gathered in mixed size-class aggregations by day and foraged beyond the grass beds at night. In autumn, these juveniles migrated to deeper habitats, coincident with new puerulus settlement in the Phyllospadix beds. Based on strong inferences from the results, it is proposed that size-dependent predation is the most important factor determining the !ife history strategy of juvenile P. interruptus. Life history tactics promoting rapid growth apparently function dually in reducing the period of high vulnerability to predation and decreasing the time required to reach sexual maturity. The Phyllospadix habitat is an excellent lobster nursery because it provides shelter from predators and possesses abundant food resources for sustaining optimum juvenile growth rates in shallow, warm water.
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Em estudos ecológicos é importante entender os processos que determinam a distribuição dos organismos. O estudo da distribuição de animais com alta capacidade de locomoção é um desafio para pesquisadores em todo o mundo. Modelos de uso de habitat são ferramentas poderosas para entender as relações entre animais e o ambiente. Com o desenvolvimento dos Sistemas de Informação Geográfica (SIG ou GIS, em inglês), modelos de uso de habitat são utilizados nas análises de dados ecológicos. Entretanto, modelos de uso de habitat frequentemente sofrem com especificações inapropriadas. Especificamente, o pressuposto de independência, que é importante para modelos estatísticos, pode ser violado quando as observações são coletadas no espaço. A Autocorrelação Espacial (SAC) é um problema em estudos ecológicos e deve ser considerada e corrigida. Nesta tese, modelos generalizados lineares com autovetores espaciais foram usados para investigar o uso de habitat dos cetáceos em relação a variáveis fisiográficas, oceanográficas e antrópicas em Cabo Frio, RJ, Brasil, especificamente: baleia-de-Bryde, Balaenoptera edeni (Capítulo 1); golfinho nariz-de-garrafa, Tursiops truncatus (Capítulo 2); Misticetos e odontocetos em geral (Capítulo 3). A baleia-de-Bryde foi influenciada pela Temperatura Superficial do Mar Minima e Máxima, no qual a faixa de temperatura mais usada pela baleia condiz com a faixa de ocorrência de sardinha-verdadeira, Sardinella brasiliensis, durante a desova (22 a 28C). Para o golfinho nariz-de-garrafa o melhor modelo indicou que estes eram encontrados em Temperatura Superficial do Mar baixas, com alta variabilidade e altas concentrações de clorofila. Tanto misticetos quanto os odontocetos usam em proporções similares as áreas contidas em Unidades de Conservação (UCs) quanto as áreas não são parte de UCs. Os misticetos ocorreram com maior frequência mais afastados da costa, em baixas temperaturas superficiais do mar e com altos valores de variabilidade para a temperatura. Os odontocetos usaram duas áreas preferencialmente: as áreas com as menores profundidades dentro da área de estudo e nas maiores profundidade. Eles usaram também habitats com águas frias e com alta concentração de clorofila. Tanto os misticetos quanto os odontocetos foram encontrados com mais frequência em distâncias de até 5km das embarcações de turismo e mergulho. Identificar habitats críticos para os cetáceos é um primeiro passo crucial em direção a sua conservação
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A radiação ultravioleta (UV) induz diversos efeitos nocivos nos organismos e a quantidade desta radiação que atinge a biosfera é afetada pela concentração de ozônio, latitude, altitude, clima e reflexão especular. As respostas de briófitas em relação aos efeitos da radiação UV e a presença de compostos que absorvem esta radiação têm sido estudadas. Sanionia uncinata, Holomitriopsis laevifolia e Leucobryum laevifolium são espécies de musgos encontrados em locais expostos a alta incidência de radiação UV e com habitats distintos. Considerando que as respostas de musgos contra os efeitos da radiação UV e seus mecanismos de proteção ainda são pouco caracterizados, o objetivo deste estudo foi investigar o potencial fotoprotetor e possíveis riscos toxicológicos associados aos extratos dos musgos S. uncinata, proveniente da Antártica e H. laevifolia e L. laevifolium, proveniente do Amazonas. Seus extratos metanólico (EM), aquoso (EA), hidroalcoólico (EH) e etanólico (EE) foram estudados com a caracterização química por absorção ao UV e visível e pela cromatografia líquida de alta eficiência; quantificação do índice total de compostos fenólicos; determinação da capacidade captadora do radical 2,2-difenil-1-picril-hidrazila a fim de avaliar as atividades antioxidantes; avaliação do potencial de fotoproteção cutânea pela determinação do fator de proteção solar; avaliações do potencial mutagênico e citototóxico, através do ensaio de Salmonella/microssoma, utilizando as cepas TA97, TA98, TA100, TA102 e TA104; do potencial fotomutagênico através do ensaio de fotomutagenicidade, usando as cepas TA102 e TA104; e investigação dos efeitos genotóxicos e fotogenotóxicos, pelo ensaio de micronúcleo e fotomicronúcleo, respectivamente, usando diferentes linhagens celulares estabelecidas. Foram encontradas atividades fotoprotetoras e antioxidantes e observou-se que os extratos se apresentaram singulares devido a sua composição química. Os resultados fotoprotetores, além dos mutagênicos/fotomutagênicos, genotóxicos/fotogenotóxicos e suas respectivas avaliações citotóxicas também permitiram selecionar extratos e suas concentrações, como promissores candidatos em fotoproteção Assim, os EA e EH de H. laevifolia e L. laevifolium apresentam, no geral, os resultados mais significativos, tornando-se potenciais para avaliações refinadas em fotoproteção e na separação de componentes que possam levar a futuras aplicações como antioxidantes e protetores solares ou como adjuvantes.
The role of substrate, flow and larval supply to recruitment of the red abalone (Haliotis rufescens)
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Precipitous declines in wild populations of the red abalone Haliotis rufescens and the eventual closure of the commercial and southern recreational fishery have led to renewed interest in supplementing wild stocks with hatchery-raised individuals. Most work to date has focused on releasing small juveniles and has had limited success. Although much is known about larval settlement, juvenile survivorship and growth of abalone, there is scanty information on natural processes in the field. The failure of many regulated fisheries worldwide suggests that both the larval and juvenile stages may be important in determining the future population, and that early juvenile mortality is more important than previously believed. This paper presents a series of experiments designed to examine factors and mechanisms that could affect settlement, survivorship, and growth of larvae and early post-settlers in the field. Laboratory trials under different flow regimes showed that red abalone larvae settled preferentially on substrates encrusted with coralline algae, and that settlement was rapid when exposed to crusts compared to other surfaces. Urchin grazing of films appeared to facilitate abalone settlement but only when urchins were removed. Initial field experiments showed that released larvae settled on natural cobble rock, and that settlement was at least one order of magnitude greater when settlement habitats were tented. I then examined post-settlement survivorship at one and two days after settlement, and found that although there was a large amount of variation, on average 10% of released larvae were found as newly-settled recruits after 1 day. Survivorship and growth of recruits were followed over at least one month in both Spring and Fall. Abalone settled at higher densities, survived better and grew faster in the warmer Fall months than in the Spring. The density of month-old abalone recruits was correlated with density of naturally-occurring gastropods in the Spring, but not in the Fall. These results suggest that settlement and survivorship can be extremely variable across space and time, and that oceanographic and local biotic conditions play a role and should be considered when planning larval seeding.
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As extensas pradarias submersas formadas pelas gramas marinhas são importantes habitats da costa, onde ocorrem interações ecológicas entre diversas espécies da vegetação subaquática, invertebrados bentônicos e peixes. As gramas marinhas e algas de deriva são conhecidas como macrófitas marinhas e, por ocuparem o mesmo tipo de substrato, são normalmente encontradas juntas, proporcionando oxigênio, alimento, proteção, abrigo além de sítios de reprodução e pastagem para os animais associados a essas pradarias. Amostras de algas de deriva e de H. wrightii foram coletadas, ao longo de transectos fixos de 50 m paralelos à Ilha do Japonês, a fim de analisar a existência de relações positivas entre as espécies de macrófitas marinhas e sua macrofauna associada, comparar as duas comunidades e avaliar a estruturação da comunidade macrofaunal bêntica do local. Os transectos foram alocados de acordo com a posição do banco de grama marinha. Observou-se que a densidade de eixos e a biomassa de H. wrightii não explicam a variação da biomassa, riqueza de espécies e diversidade (Índice de Simpson) das algas de deriva. A grande movimentação das algas de deriva ao longo do banco de grama marinha faz com que elas se homogeneízem e ocupem diferentes lugares ao acaso na pradaria, muitos desses locais com baixa biomassa de H. wrightii devido à grande variabilidade na distribuição dessa espécie no local de estudo. Os descritores ecológicos da grama marinha também não tiveram relações positivas com sua macrofauna bêntica associada. A comunidade macrofaunal associada às gramas marinhas foi mais densa, rica e diversa do que a comunidade macrofaunal associada às algas de deriva. Os moluscos Anomalocardia flexuosa, Cerithium atratum, Ostrea sp, Tellina lineata e Divalinga quadrissulcata dominaram o ambiente de gramas marinhas. A maior complexidade estrutural das algas de deriva forneceu um habitat protegido mais atrativo para os crustáceos como, Pagurus criniticornis, Cymadusa filosa e Batea catharinensis. A malacofauna associada às algas não foi abundante, mas um novo registro foi a ocorrência do bivalve invasor Lithopaga aristatus, perfurando uma concha de Ostrea sp. As relações entre os descritores da biomassa algal foram comprovadas para a maioria dos descritores de sua fauna associada. As relações das macrófitas marinhas com a macrofauna total associada seguiram o mesmo padrão das relações das algas de deriva. As análises de agrupamento e ordenação mostraram que as comunidades macrofaunais bênticas do local são estruturadas de acordo com os táxons dos organismos associados mais dominantes influenciados pelo tipo de vegetação basibionte (algas de deriva ou grama marinha). Destaca-se com o presente estudo a importância de medidas de maior proteção no local para a preservação e manutenção do ecossistema da Ilha do Japonês, RJ, Brasil
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Em uma das maiores florestas urbanas do mundo, o Parque Nacional da Tijuca no Rio de Janeiro, se situa uma espécie do gênero Hylodes: Hylodes nasus. Sobre esta espécie existem poucos estudos, os principais relatam sobre seu comportamento territorialista, suas vocalizações e sobre seu giríno. Neste trabalho, nós estudamos como se dá a atividade, o uso do hábitat, o esforço reprodutivo e a dieta de H. nasus. Esta espécie é endêmica do Maciço da Tijuca e está restrita a riachos, o qual tem se provado ser bastante relacionado ao seu modo de reprodução. Os dados revelaram que a espécie tem uma atividade essencialmente diurna que está muita ligada ao fotoperíodo e que essa atividade tem uma tendência a diminuição no período do meio do dia. Alguns trabalhos tem atribuído a diminuição da atividade de outras espécies à redução da intensidade luminosa alcançando seus sítios de vocalização, devido à posição do sol. A espécie, quando ativa, frequentemente permanece sobre pedras e perto de quedas dágua, que parecem ter um papel importante na sua atividade de vocalização. Verificamos uma mudança no uso dos micro-habitats entre o período diurno e o período noturno. Quanto à dieta os dados indicaram que esta é uma espécie que se alimenta predominantemente de um pequeno grupo de insetos (Diptera, Formicidae, Coleoptera e Hymenoptera). Ainda assim foi encontrado um grande espectro de presas presentes nos seus estômagos, principalmente de presas abundantes em riachos da Mata Atlântica. Tal fato pode indicar um comportamento mais oportunista e generalista por parte da espécie. O esforço reprodutivo empregado pelas fêmeas da espécie tendeu a ser maior no número de ovócitos do que no tamanho destes quando comparamos estes parâmetros às outras espécies de Hylodes. O tamanho e massa das fêmeas também tiveram uma relação positiva com o número respectivo de ovócitos encontrados nelas
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Os peixes são vertebrados que vivem em vários habitats. Adaptações de sua fisiologia e de sua bioquímica são estudadas para entender como conseguem sobreviver aos desafios presentes em cada ambiente. A diminuição da concentração de oxigênio dissolvido na água é um fenômeno natural cíclico em águas do Pantanal e da Amazônia. A crescente poluição antrópica dos rios da Amazônia e do Pantanal pode, somada à hipoxia, oferecer ameaça à permanência de muitas espécies de peixes. Ao estudarmos a carboxilesterase (CarbE), enzima importante para a biotransformação de xenobióticos, observamos que sua atividade diminuía em plasma de pacu, um peixe típico do Pantanal, mantido em hipoxia durante 42 horas. As carboxilesterases participam de inúmeras reações químicas no organismo, incluindo uma transesterificação capaz de produzir ésteres etílicos tóxicos de ácido graxo (FAEE, fatty acid ethyl esters) a partir de etanol e ésteres de ácidos graxos. Já que a diminuição da atividade de CarbE poderia ser uma vantagem, pois que o etanol (um produto da glicólise em peixes sob hipoxia) seria menos esterificado, resolvemos saber mais sobre a bioquímica da CarbE do plasma e do fígado de pacus. Os pacus foram submetidos à hipoxia por diminuição da concentração até 0,5 mg O2/L por meio de borbulhamento de nitrogênio na água. Os animais ficaram nessas condições por 42 horas, quando então coletamos sangue e retiramos seus fígados. A atividade de CarbE ensaiada foi 50% menor no soro e 25% menor nos microssomos de fígado se comparada com a de peixes sob 6 mg O2/L. A CarbE isolada do soro dos pacus em normoxia possui massa molecular relativa de 56.000. A eletroforese em gel desnaturante com a fração purificada rendeu três bandas, mas o gel nativo apresentou só duas bandas com atividades sobre α-naftil acetato. Inferimos que mais do que uma isoforma da enzima está no plasma dos pacus. A CarbE isolada do soro não possui atividade de lipase sobre o Tween 20, mas os microssomos dos fígados dos animais em normoxia e hipoxia possuem. No entanto, a CarbE possui atividade sobre acil-CoA assim como o microssomo de fígado. A enzima pura apresenta Vmáx três vezes maior e uma KM quatro vezes maior do que a atividade presente nos microssomos. Além disso, os microssomos do fígado dos pacus em normoxia podem hidrolisar acil-CoA com o dobro da velocidade daqueles em hipoxia. A atividade clássica de CarbE do soro foi inibida por 4-HNE a 4 mM. A atividade de acil-CoA dos microssomos de fígado também foi sensível a 4-HNE a 4 mM, enquanto 2 mM de 4-HNE inibiu metade desta atividade do soro.
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The transition between freshwater and marine environments is associated with high mortality for juvenile anadromous salmonids, yet little is known about this critical period in many large rivers. To address this deficiency, we investigated the estuarine ecology of juvenile salmonids and their associated fish assemblage in open-water habitats of the lower Columbia River estuary during spring of 2007–10. For coho (Oncorhynchus kisutch), sockeye (O. nerka), chum (O. keta), and yearling (age 1.0) Chinook (O. tshawytscha) salmon, and steelhead (O. mykiss), we observed a consistent seasonal pattern characterized by extremely low abundances in mid-April, maximum abundances in May, and near absence by late June. Subyearling (age 0.0) Chinook salmon were most abundant in late June. Although we observed interannual variation in the presence, abundance, and size of juvenile salmonids, no single year was exceptional across all species-and-age classes. We estimated that >90% of juvenile Chinook and coho salmon and steelhead were of hatchery origin, a rate higher than previously reported. In contrast to juvenile salmonids, the abundance and composition of the greater estuarine fish assemblage, of which juvenile salmon were minor members, were extremely variable and likely responding to dynamic physical conditions in the estuary. Comparisons with studies conducted 3 decades earlier suggest striking changes in the estuarine fish assemblage—changes that have unknown but potentially important consequences for juvenile salmon in the Columbia River estuary.
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We examined the reactions of fishes to a manned submersible and a remotely operated vehicle (ROV) during surveys conducted in habitats of rock and mud at depths of 30–408 m off central California in 2007. We observed 26 taxa for 10,550 fishes observed from the submersible and for 16,158 fishes observed from the ROV. A reaction was defined as a distinct movement of a fish that, for a benthic or hovering individual, was greater than one body length away from its initial position or, for a swimming individual, was a change of course or speed. Of the observed fishes, 57% reacted to the ROV and 11% reacted to the submersible. Aggregating species and those species initially observed off the seafloor reacted most often to both vehicles. Fishes reacted more often to each vehicle when they were >1 m above the seafloor (22% of all fishes >1 m above the seafloor reacted to the submersible and 73% to the ROV) than when they were in contact with the seafloor (2% of all reactions to the submersible and 18% to the ROV). Fishes reacted by swimming away from both vehicles rather than toward them. Consideration of these reactions can inform survey designs and selection of survey tools and can, thereby, increase the reliability of fish assemblage metrics (e.g., abundance, density, and biomass) and assessments of fish and habitat associations.
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With the use of a baited stereo-video camera system, this study semiquantitatively defined the habitat associations of 4 species of Lutjanidae: Opakapaka (Pristipomoides filamentosus), Kalekale (P. sieboldii), Onaga (Etelis coruscans), and Ehu (E. carbunculus). Fish abundance and length data from 6 locations in the main Hawaiian Islands were evaluated for species-specific and size-specific differences between regions and habitat types. Multibeam bathymetry and backscatter were used to classify habitats into 4 types on the basis of substrate (hard or soft) and slope (high or low). Depth was a major influence on bottomfish distributions. Opakapaka occurred at depths shallower than the depths at which other species were observed, and this species showed an ontogenetic shift to deeper water with increasing size. Opakapaka and Ehu had an overall preference for hard substrate with low slope (hard-low), and Onaga was found over both hard-low and hard-high habitats. No significant habitat preferences were recorded for Kalekale. Opakapaka, Kalekale, and Onaga exhibited size-related shifts with habitat type. A move into hard-high environments with increasing size was evident for Opakapaka and Kalekale. Onaga was seen predominantly in hard-low habitats at smaller sizes and in either hard-low or hard-high at larger sizes. These ontogenetic habitat shifts could be driven by reproductive triggers because they roughly coincided with the length at sexual maturity of each species. However, further studies are required to determine causality. No ontogenetic shifts were seen for Ehu, but only a limited number of juveniles were observed. Regional variations in abundance and length were also found and could be related to fishing pressure or large-scale habitat features.
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The adjacency of 2 marine biogeographic regions off Cape Hatteras, North Carolina (NC), and the proximity of the Gulf Stream result in a high biodiversity of species from northern and southern provinces and from coastal and pelagic habitats. We examined spatiotemporal patterns of marine mammal strandings and evidence of human interaction for these strandings along NC shorelines and evaluated whether the spatiotemporal patterns and species diversity of the stranded animals reflected published records of populations in NC waters. During the period of 1997–2008, 1847 stranded animals were documented from 1777 reported events. These animals represented 9 families and 34 species that ranged from tropical delphinids to pagophilic seals. This biodiversity is higher than levels observed in other regions. Most strandings were of coastal bottlenose dolphins (Tursiops truncatus) (56%), harbor porpoises (Phocoena phocoena) (14%), and harbor seals (Phoca vitulina) (4%). Overall, strandings of northern species peaked in spring. Bottlenose dolphin strandings peaked in spring and fall. Almost half of the strandings, including southern delphinids, occurred north of Cape Hatteras, on only 30% of NC’s coastline. Most stranded animals that were positive for human interaction showed evidence of having been entangled in fishing gear, particularly bottlenose dolphins, harbor porpoises, short-finned pilot whales (Globicephala macrorhynchus), harbor seals, and humpback whales (Megaptera novaeangliae). Spatiotemporal patterns of bottlenose dolphin strandings were similar to ocean gillnet fishing effort. Biodiversity of the animals stranded on the beaches reflected biodiversity in the waters off NC, albeit not always proportional to the relative abundance of species (e.g., Kogia species). Changes in the spatiotemporal patterns of strandings can serve as indicators of underlying changes due to anthropogenic or naturally occurring events in the source populations.
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Black Sea Bass (Centropristis striata) in the mid-Atlantic Bight undertake seasonal cross-shelf movements to occupy inshore rocky reefs and hardbottom habitats between spring and fall. Shelf-wide migrations of this stock are well documented, but movements and home ranges of fish during their inshore residency period have not been described. We tagged 122 Black Sea Bass with acoustic transmitters at a mid-Atlantic reef to estimate home-range size and factors that influence movements (>400 m) at a 46.1-km2 study site between May and November 2003. Activity of Black Sea Bass was greatest and most consistent during summer but declined rapidly in September as water temperatures at the bottom of the seafloor increased on the inner shelf. Black Sea Bass maintained relatively large home ranges that were fish-size invariant but highly variable (13.7–736.4 ha), underscoring the importance of large sample sizes in examination of population-level characteristics of mobile species with complex social interactions. On the basis of observed variations in movement patterns and the size of home ranges, we postulate the existence of groups of conspecifics that exhibit similar space-use behaviors. The group of males released earlier in the tagging period used larger home ranges than the group of males released later in our study. In addition, mean activity levels and the probability of movement among acoustic stations varied among groups of fish in a complex manner that depended on sex. These differences in movement behaviors may increase the vulnerability of male fish to passive fishing gears, further exacerbating variation in exploitation rates for this species among reefs.
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Stichaeidae, commonly referred to as pricklebacks, are intertidal and subtidal fishes primarily of the North Pacific Ocean. Broad distribution in relatively inaccessible and undersampled habitats has contributed to a general lack of information about this family. In this study, descriptions of early life history stages are presented for 25 species representing 18 genera of stichaeid fishes from the northeastern Pacific Ocean, Bering Sea, and Arctic Ocean Basin. Six of these species also occur in the North Atlantic Ocean. Larval stages of 16 species are described for the first time. Additional information or illustrations intended to augment previous descriptions are provided for nine species. For most taxa, we present adult and larval distributions, descriptions of morphometric, meristic, and pigmentation characters, and species comparisons, and we provide illustrations for preflexion through postflexion or transformation stages. New counts of meristic features are reported for several species.