Synagapetus dubitans, a caddisfly new to Britain

The caddisfly species Synagapetus dubitans has been found recently for the first time in the UK in 2010. This study reports on the sampling and discovery of that species in North Yorkshire. A list of sites where S. dubitans (either as larvae or adults) has been found is given

Glossoma intermedium survey. Scotland, April 5th to April 10th 2012

The British Glossomatidae contains seven species, split between the genera Glossosoma, Agapetus and Synagapetus. One species, Glossosoma intermediumhas not been recorded in England since 2003. This was found in a side stream of Hayeswater gill in the Lake District. The main purpose of this survey was to try and locate and record Glossosoma intermedium and was a follow up to a similar survey we carried out in the Glennshee area of Scotland during April 2011. Additionally, as in the 2011 survey it also made sense that while looking for the larvae, pupae and adults of Glossosoma intermediumwe could also record other species of caddisfly (Trichoptera), mayfly (Ephemeroptera) and stonefly (Plecoptera).

Ecology and growth of juvenile California spiny lobster, Panulirus interruptus (Randall)

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.

The role of substrate, flow and larval supply to recruitment of the red abalone (Haliotis rufescens)

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.

The larval stages of the calanoid copepod Eurytemora hirundoides (Nordquist)

Most Copepoda pass through, first, a series of nauplius stages, and then through a series of copepodid stages (or cyclops stages), in which the general form of the adult is assumed. ... In the first place, the differentiation between the larvae of the various copepod species to be found in the plankton, both marine and fresh water, greatly augments the value and accuracy of quantitative and qualitative plankton analyses, because many species spend a large portion of their life span in an immature condition. In the second place, the taxonomy of the Copepoda is admittedly not completely satisfactory ...

The food habits of hatchery-produced pond-cultured shad (Alosa sapidissima) reared to a length of two inches

The present study was aimed at determining the food habits of hatchery-produced, pond-cultured shad (Alosa sapidissima) reared to a total length of approximately two inches. More specifically, the objectives were to determine: (1) That point in life at which young shad start to consume food; (2) What type or types of food the young shad consume at the onset of feeding; (3) Food changes, if any, which occur with age and growth in size up to the arbitrarily designated total length of two inches. The plan was that the shad larvae be introduced into an outdoor rearing pond previously fertilized, and that the larvae be dependent upon the plankton for food as they would be under natural conditions.

Inshore spawning of cobia (Rachycentron canadum) in South Carolina

We documented inshore spawning of the recreationally important cobia (Rachycentron canadum) in Port Royal Sound (PRS) and St. Helena Sound (SHS), South Carolina, during the period from April to June in both 2007 and 2008. Histological analysis of ovaries confirmed the presence of actively spawning females inshore, and gonadosomatic index (GSI) values from females collected inshore (mean=7.8) were higher than the values from females caught offshore (mean=5.6); both of these mean values indicate that spawning occurred locally. Additionally, we conducted an ichthyoplankton survey in 2008 and found cobia eggs and larvae as far as 10 and 15 km inshore from the mouths of SHS and PRS, respectively. A study of egg development that we conducted in 2007 and 2008 using hatchery-reared cobia eggs provided descriptions of embryological development of cobia. Comparison of visual and quantitative characteristics of the field-collected eggs with those of the hatchery-reared eggs allowed positive identification of eggs collected in plankton samples. The ages of field-collected eggs and presence of females with hydrated oocytes in PRS and SHS observed in our ichthyoplankton survey and histological analysis indicated that wild cobia spawn in the afternoon and early evening. The inshore migration of cobia from April to June, the presence of actively spawning females, significantly higher GSI values, and the collection of eggs inside PRS and SHS all confirm that these estuaries provide spawning habitat for cobia. Because of the potential for heavy exploitation by recreational anglers as cobia move inshore to spawn in South Carolina, current management strategies may require review.

Evaluation of the In Situ Ichthyoplankton Imaging System (ISIIS): comparison with the traditional (bongo net) sampler

Plankton and larval fish sampling programs often are limited by a balance between sampling frequency (for precision) and costs. Advancements in sampling techniques hold the potential to add considerable efficiency and, therefore, add sampling frequency to improve precision. We compare a newly developed plankton imaging system, In Situ Ichthyoplankton Imaging System (ISIIS), with a bongo sampler, which is a traditional plankton sampling gear developed in the 1960s. Comparative sampling was conducted along 2 transects ~30–40 km long. Over 2 days, we completed 36 ISIIS tow-yo undulations and 11 bongo oblique tows, each from the surface to within 10 m of the seafloor. Overall, the 2 gears detected comparable numbers of larval fishes, representing similar taxonomic compositions, although larvae captured with the bongo were capable of being identified to lower taxonomic levels, especially larvae in the small (<5 mm), preflexion stages. Size distributions of the sampled larval fishes differed considerably between these 2 sampling methods, with the size range and mean size of larval fishes larger with ISIIS than with the bongo sampler. The high frequency and fine spatial scale of ISIIS allow it to add considerable sampling precision (i.e., more vertical sections) to plankton surveys. Improvements in the ISIIS technology (including greater depth of field and image resolution) should also increase taxonomic resolution and decrease processing time. When coupled with appropriate net sampling (for the purpose of collecting and verifying the identification of biological samples), the use of ISIIS could improve overall survey design and simultaneously provide detailed, process-oriented information for fisheries scientists and oceanographers.

Using measurements of muscle cell nuclear RNA with flow cytometry to improve assessment of larval condition of Walleye Pollock (Gadus chalcogrammus)

Nuclear RNA and DNA in muscle cell nuclei of laboratory-reared larvae of Walleye Pollock (Gadus chalcogrammus) were simultaneously measured through the use of flow cytometry for cell-cycle analysis during 2009–11. The addition of nuclear RNA as a covariate increased by 4% the classification accuracy of a discriminant analysis model that used cell-cycle, temperature, and standard length to measure larval condition, compared with a model without it. The greatest improvement, a 7% increase in accuracy, was observed for small larvae (<6.00 mm). Nuclear RNA content varied with rearing temperature, increasing as temperature decreased. There was a loss of DNA when larvae were frozen and thawed because the percentage of cells in the DNA synthesis cell-cycle phase decreased, but DNA content was stable during storage of frozen tissue.

Larval development and identification of the genus Triglops (Scorpaeniformes: Cottidae)

Prior to Pietsch’s (1993) revision of the genus Triglops, identification of their larvae was difficult; six species co-occur in the eastern North Pacific Ocean and Bering Sea and three co-occur in the western North Atlantic Ocean. We examined larvae from collections of the Alaska Fisheries Science Center and Atlantic Reference Centre and used updated meristic data, pigment patterns, and morphological characters to identify larvae of Triglops forficatus, T. macellus, T. murrayi, T. nybelini, T. pingeli, and T. scepticus; larvae of T. metopias, T. dorothy, T. jordani, and T. xenostethus have yet to be identified and are thus not included in this paper. Larval Triglops are characterized by a high myomere count (42–54), heavy dorsolateral pigmentation on the gut, and a pointed snout. Among species co-occurring in the eastern North Pacific Ocean, T. forficatus, T. macellus, and T. pingeli larvae are distinguished from each other by meristic counts and presence or absence of a series of postanal ventral melanophores. Triglops scepticus is differentiated from other eastern North Pacific Ocean larvae by having 0–3 postanal ventral melanophores, a large eye, and a large body depth. Among species co-occurring in the western North Atlantic Ocean, T. murrayi and T. pingeli larvae are distinguished from each other by meristic counts (vertebrae, dorsal-fin rays, and anal-fin rays once formed), number of postanal ventral melanophores, and first appearance and size of head spines. Triglops nybelini is distinguished from T. murrayi and T. pingeli by a large eye, pigment on the lateral line and dorsal midline in flexion larvae, and a greater number of dorsal-fin rays and pectoral-fin rays once formed.

Bering Sea FOCI Final Report

To develop an understanding of stock structure and recruitment variation in Bering Sea pollock, the Coastal Ocean Program of the National Oceanic and Atmospheric Administration (NOAA) funded an 7-year (1991-1997), interdisciplinary project named Bering Sea Fisheries-Oceanography Coordinated Investigations (BS FOCI; Schumacher and Kendall, 1995) for which NOAA and academic researchers were selected through a competitive process (Macklin, this report). The project goals, based on recommendations from an international symposium on pollock (Aron and Balsiger, 1989) were to (1) determine stock structure in the Bering Sea and its potential relationship to physical oceanography, and (2) examine recruitment processes in the eastern Bering Sea. Both of these have direct implication to management. An integrated set of field, laboratory, and modeling studies were established to accomplish these goals. To address the first goal, project objectives were to establish details of oceanic circulation relevant to larval dispersal and separation of stocks, and determine if unique chemical or genetic indicators existed for different stocks. The recruitment component of BS FOCI, addressing the second goal, focused on understanding causes of variable mortality of pollock larvae in the different habitats of the eastern Bering Sea. The emphasis of recruitment studies was to determine the dominant physical oceanographic features (turbulence, temperature, and transport) that could influence survival of pollock larvae, and investigate factors controlling food production for the larvae. A later component contrasted juvenile habitat in three hydrographic regimes around the Pribilof Islands (Brodeur, this report).

Synthesis of summer flounder habitat parameters

The summer flounder, Paralichthys dentatus, is overexploited and is currently at very low levels of abundance. This is reflected in the compressed age structure of the population and the low catches in both commercial and recreational fisheries. Declining habitat quantity and quality may be contributing to these declines, however we lack a thorough understanding of the role of habitats in the population dynamics of this species. Stock structure is unresolved and current interpretations, depending on the technique and study area, suggest that there may be two or three spawning populations. If so, these stocks may have differing habitat requirements. In response to this lack of knowledge, this document summarizes and synthesizes the available information on summer flounder habitat in all life history stages (eggs, larvae, juveniles and adults) and identifies areas where further research is needed. Several levels of investigation were conducted in order to produce this document. First, an extensive search for summer flounder habitat information was made, which included both the primary and gray literature as well as unanalyzed data. Second, state and federal fisheries biologists and resource managers in all states within the primary range of summer flounder (Massachusetts to Florida) were interviewed along with a number of fish ecologists and summer flounder experts from the academic and private sectors. Finally, information from all sources was analyzed and synthesized to form a coherent overview. This document first presents an overview of the economic importance and current status of summer flounder (Chapter 1). It then summarizes our present state of knowledge of summer flounder distribution, life history patterns and stock identification (Chapter 2). This is followed by a synopsis of habitat requirements during each life history stage. For convenience, this is presented by general habitat as offshore eggs (Chapter 3), offshore larvae (Chapter 4), estuarine larvae (Chapter 5), estuarine juveniles (Chapter 6), offshore juveniles (Chapter 7) and estuarine and offshore adults (Chapter 8). In several instances, previously undigested data sets are analyzed to provide more detailed information, especially for estuarine juveniles. The information is then discussed in terms of its relevance to resource managers (Chapter 9).

The distribution of larval fishes of the Charleston Gyre Region off the southeastern United States in winter shaped by mesoscale, cyclonic eddies

Serial, cyclonic, mesoscale eddies arise just north of the Charleston Bump, a topographical rise on the continental slope and Blake Plateau, and characterize the U.S. outer shelf and upper slope in the region of the Charleston Gyre. This region was transected during the winters of 2000, 2001, and 2002, and hydrographic data and larval fishes were collected. The hydrodynamics of the cyclonic eddies of the Charleston Gyre shape the distribution of larval fishes by mixing larvae from the outer continental shelf and the Gulf Stream and entraining them into the eddy circulation at the peripheral margins, the wrap-around filaments. Over all years and transects (those that intercepted eddies and those that did not), chlorophyll a concentrations, zooplankton displacement volumes, and larval fish concentrations were positively correlated. Chlorophyll a concentrations were highest in filaments that wrapped around eddies, and zooplankton displacement volumes were highest in the continental shelf–Gulf Stream–frontal mix. Overall, the concentration of all larval fishes declined from inshore to offshore with highest concentrations occurring over the outer shelf. Collections produced larvae from 91 fish families representing continental shelf and oceanic species. The larvae of shelf-spawned fishes—Atlantic Menhaden Brevoortia tyrannus, Round Herring Etrumeus teres, Spot Leiostomus xanthurus, and Atlantic Croaker Micropogonias undulatus—were most concentrated over the outer shelf and in the continental shelf–Gulf Stream–frontal mix. The larvae of ocean-spawned fishes—lanternfishes, bristlemouths, and lightfishes—were more evenly dispersed in low concentrations across the outer shelf and upper slope, the highest typically in the Gulf Stream and Sargasso Sea, except for lightfishes that were highest in the continental shelf–Gulf Stream–frontal mix. Detrended correspondence analysis rendered groups of larval fishes that corresponded with a gradient between the continental shelf and Gulf Stream and Sargasso Sea. Eddies propagate northeastward with a residence time on the outer shelf and upper slope of ∼1 month, the same duration as the larval period of most fishes. The pelagic habitat afforded by eddies and fronts of the Charleston Gyre region can be exploited as nursery areas for feeding and growth of larval fishes within the southeastern Atlantic continental shelf ecosystem of the U.S. Eddies, and the nursery habitat they provide, translocate larvae northeastward.

A biogeographic assessment of the Samoan Archipelago

This report examines the marine biogeography of the Samoan Archipelago (~14º S latitude along the international date-line) with a focus on regional ocean climate, connectivity among islands due to larval transport, distributions of reef fish and coral communities, and the extent of existing marine protected areas. Management decisions and prior assessments in the archipelago have typically been split along the international political boundary between the islands of Samoa and those of American Samoa despite their close proximity and shared resources. A key goal in this assessment was to compile data from both jurisdictions and to conduct the characterization across the entire archipelago. The report builds upon earlier assessments by re-analyzing and interpreting many pre-existing datasets, adding more recent biogeographic data sources, and by combining earlier findings into a multidisciplinary summary of marine biogeography. The assessment is divided into 5 chapters and supporting appendices. Each chapter was written and reviewed in collaboration with subject matter specialists and local experts. In Chapter 1, a short introduction to the overall scope and approach of the report is provided. In Chapter 2, regional ocean climate is characterized using remote sensing datasets and discussed in the context of local observations. In Chapter 3, regional ocean currents and transport of coral and fish larvae are investigated among the islands of the archipelago and surrounding island nations. In Chapter 4, distinct reef fish and coral communities across the archipelago are quantified on the basis of overall biodiversity, abundance, and community structure. In Chapter 5, the existing network of MPAs in American Samoa is evaluated based on the habitats, reef fish, and coral communities that are encompassed. Appendices provide analytical details omitted from some chapters for brevity as well as supplemental datasets needed as inputs for the main chapters in the assessment. Appendices include an inventory of regional seamounts, a description of shore to shelf edge benthic maps produced for Tutuila, analytical details of reef fish and coral datasets, and supplemental information on the many marine protected areas in American Samoa.

Recruitment and spawning-stock biomass distribution of bay anchovy (Anchoa mitchilli) in Chesapeake Bay

Recruitment of bay anchovy (Anchoa mitchilli) in Chesapeake is related to variability in hydrological conditions and to abundance and spatial distribution of spawning stock biomass (SSB). Midwater-trawl surveys conducted for six years, over the entire 320-km length of the bay, provided information on anchovy SSB, annual spatial patterns of recruitment, and their relationships to variability in the estuarine environment. SSB of anchovy varied sixfold in 1995–2000; it alone explained little variability in young-of-the-year (YOY) recruitment level in October, which varied ninefold. Recruitments were low in 1995 and 1996 (47 and 31 Z 109) but higher in 1997–2000 (100 to 265 Z 109). During the recruitment process the YOY population migrated upbay before a subsequent fall-winter downbay migration. The extent of the downbay migration by maturing recruits was greatest in years of high freshwater input to the bay. Mean dissolved oxygen (DO) was more important than freshwater input in controlling distribution of SSB and shifts in SSB location between April– May (prespawning) and June–August (spawning) periods. Recruitments of bay anchovy were higher when mean DO was lowest in the downbay region during the spawning season. It is hypothesized that anchovy recruitment level is inversely related to mean DO concentration because low DO is associated with high plankton productivity in Chesapeake Bay. Additionally, low DO conditions may confine most bay anchovy spawners to the downbay region, where production of larvae and juveniles is enhanced. A modified Ricker stock-recruitment model indicated density-compensatory recruitment with respect to SSB and demonstrated the importance of spring-summer DO levels and spatial distribution of SSB as controllers of bay anchovy recruitment.