History of Oystering in the United States and Canada, Featuring the Eight Greatest Oyster Estuaries

Oyster landings in the United States and Canada have been based mainly on three species, the native eastern oyster, Crassostrea virginica, native Olympia oyster, Ostreola conchaphila, and introduced Pacific oyster, C. gigas. Landings reached their peak of around 27 million bushels/year in the late 1800's and early 1900's when eastern oysters were a common food throughout the east coast and Midwest. Thousands of people were involved in harvesting them with tongs and dredges and in shucking, canning, packing, and transporting them. Since about 1906, when the United States passed some pure food laws, production has declined. The causes have been lack of demand, siltation of beds, removal of cultch for oyster larvae while harvesting oysters, pollution of market beds, and oyster diseases. Production currently is about 5.6 million bushels/year.

Menhaden: The Resource, The Industry, and a Management History

PREFACE: Four species of menhaden, Brevoortia spp., are found along the Atlantic and Gulf of Mexico coasts of the United States. The Atlantic menhaden, B. tyrannus, is found from Nova Scotia, Can., to West Palm Beach, Fla.; the yellowfin menhaden, B. smithi, is found from Cape Lookout, N. C., to the Mississippi River Delta, La.;the Gulf menhaden, B. patronus, is found from Cape Sable, Fla., to Veracruz, Mex.; and the finescale menhaden, B. gunteri, is found from the Mississippi River Delta, La., to Campeche, Mex. Menhaden are euryhaline species that inhabit coastal and inland tidal waters. Spawning occurs principally at sea (in northern areas some spawning occurs in bays and sounds). Eggs hatch at sea and the larvae are moved to estuaries by ocean currents where they metamorphose and develop as juveniles.

The Feasibility of Enhancing Red Sea Urchin, Strongylocentrotus iranciscanus, Stocks in California: An Analysis of the Options

The California fishery for red sea urchins, Strongylocentrotus franciscanus, has undergone explosive growth in recent years and is approaching full exploitation. Thus, there is considerable interest in enhancing stocks to maintain a high rate of landings. Fishable stocks of red sea urchins in different areas appear to be limited at three stages in their life history: By the availability of larvae, by the survival of newly settled to mid-sized animals, and by the food available to support growth and reproduction of larger animals. Here I review other efforts, notably the extensive Japanese work, to enhance fishable stocks of benthic marine invertebrates, and consider the potential options for red sea urchins at different points of limitation. These include collecting or culturing seed for outplanting, physical habitat improvement measures, improving the food supply, and conservation measures to protect existing stocks until alternate methods are proven and in place. The options are compared in terms of biological feasibility, capital and labor requirements, and potential implications for change in the structure of the fishing industry.

Life history and production of Capitella capitata (Polychaeta: Capitellidae) in Río de la Plata Estuary (Argentina)

A benthic survey was carried out from November 1998 to December 1999 in the tidal flats of Bahía Samborombón (Río de la Plata estuary, Argentina), in order to study the population structure, reproductive aspects, growth and secondary production of Capitella capitata (Fabricius, 1780). Growth was analyzed using ELEFAN routine, and the secondary production was estimated by Hynes and Coleman's method (1968). C. capitata did not present periods of very important recruitments throughout the year; however, the abundance of smallest size classes was higher during summer and autumn. The summer cohort showed a growth rate (K) of 2.05 and a seasonal growth oscillation (C) of 0.6, pointing out that worms grew very slowly during winter months. The life span of this cohort was 13 months. The autumn cohort showed a lower growth rate (K= 1.5) and its growth was lowest during winter. The life span was 15 months for this cohort. C. capitata in Punta Rasa presented an extended reproductive period, with absence of activity during winter months. The type of eggs and larvae suggest that C. capitata has benthic larval development in the study area, destining its reproductive effort to the production of a low number of eggs, and assuring larvae survival through incubation in brooding tubes. The annual mean biomass in Punta Rasa was 0.117 g m-2 (AFDW), with a mean secondary production of 0.23 g m-2 y-1 and a P/B ratio of 1.96 y-1. The relatively low density, biomass production and P/B ratio of C. capitata in Punta Rasa can be considered as reference values for this species inhabiting undisturbed or moderately disturbed areas.

Crab fisheries in Cambodia and the development of crab banks

The crab (swimming crab; Portunus pelagicus) fishery in coastal Cambodia appears to have declined in recent years due to over-fishing and a growth in the number of fishermen, but remains an important source of income for households along the coast. Several initiatives have started since 2007, with support from NGOs, international organizations and the Fisheries Administration (FiA), to test stock enhancement techniques through the release of crab larvae. The so-called “crab bank” initiative involves keeping harvested gravid crabs alive in cages for a few days until they spawn, instead of immediately selling them for consumption or processing. In Cambodia, this initiative has developed within the framework of Community Fisheries (CFis) and thus implies a communitybased approach. The FiA has promoted the continuation of such initiatives; however, the nature of crab fisheries and the results from crab bank initiatives have not been documented in detail. The scope of this study was to understand the diversity of approaches to crab bank development in Cambodia, as well as their operational status and the challenges faced at differen

Die vertikale Verteilung von Heringslarven im Greifswalder Bodden

Kurzfassung Im Rahmen einer Bachelorarbeit wurde untersucht, ob die Larven des frühjahrslaichenden Herings der westlichen Ostsee im Greifswalder Bodden eine inhomogene vertikale Verteilung aufweisen, da in bisherigen Studien aufgrund der niedrigen Gewässertiefe des Boddens von hydrografischer Durchmischung und somit homogener Ichthyoplanktonverteilung ausgegangen wurde. Dazu wurden zwei Nullhypothesen überprüft, eine, die annimmt, dass Heringslarven allgemein im Greifswalder Bodden homogen verteilt sind, eine zweite, nach der auch verschiedenen Längenklassen der Heringe homogen verteilt sind. Die Proben, die Mitte April an drei verschiedenen Stationen im Greifswalder Bodden genommen wurden, zeigten signifikante Unterschiede der Larvenabundanzen allgemein zwischen den beprobten Tiefenstufen als auch der Längenklassen zwischen den Tiefenstufen, sodass beide Nullhypothesen abzulehnen sind. Eine homogene Verteilung der Heringslarven kann ausgeschlossen werden. Abstract Larvae of the Western Baltic Spring Spawning Herring were sampled in the Greifswalder Bodden in the course of a Bachelor Thesis to investigate whether they are inhomogeneously vertically distributed. Previous research assumed homogeneous vertical distribution because of the shallowness of the Greifswalder Bodden due to hydrographical mixing of the water and the ichthyoplankton. Two null hypotheses were tested, one which presumes even vertical distribution of the herring larvae and another which presumes even vertical distribution within different length classes in the Greifswalder Bodden. Sampling took place at three different stations in the Greifswalder Bodden during April and results showed significant differences of the larvae abundances between the sampled depths and also significant differences of the length classes between the sampled depths. Therefore both null hypotheses can be rejected and a homogeneous vertical distribution of the herring larvae in the Greifswalder Bodden can be excluded.

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.

Filogeografia e evolução molecular de lagostas sapateiras (Scyllarides spp.) da América do Sul

Nos últimos anos, duas espécies de lagostas sapateiras, Scyllarides brasiliensis e S. deceptor, vêm se destacando nos desembarques pesqueiros de lagostas do Atlântico Sul Ocidental. Para espécies comercialmente importantes, o desenvolvimento de estudos que permitam conhecer a variabilidade e entender a dinâmica populacional é fundamental. Assim, o objetivo do primeiro capítulo desta tese foi avaliar a diversidade genética e a estrutura populacional dessas duas lagostas ao longo de aprox. 2.800 km da costa da América do Sul. Para as análises, foram empregados marcadores mitocondriais (citocromo oxidase I: COI; e a região controle: RC) e marcadores nucleares (13 loci de microssatélites desenvolvidos nesta tese). As duas espécies apresentaram altos níveis de variabilidade (S. deceptor: N = 200, mtDNA: h > 0,841, π > 0,005; microssatélites: He = 0,685; S. brasiliensis: N = 211, He = 0,554), distribuídos homogeneamente entre as localidades (S. deceptor: ΦST < -0,004, ΦCT < 0,016, FST global = 0,001, Dest global = 0,003, FCT < 0,002, P > 0,05, K = 1; S. brasiliensis: FST global = 0,004, Dest global = 0,001, FCT < 0,004, P > 0,05, K = 1). A ausência de estruturação nas duas espécies pode estar relacionada a características biológicas que promovem a conectividade entre localidades geograficamente distantes, como alta fecundidade e alto potencial de dispersão das larvas planctônicas. Além disso, os dados mitocondriais sugerem que a história demográfica de S. deceptor foi marcada por eventos de expansão populacionais e geográficos possivelmente relacionados às condições ambientais favoráveis dos episódios interglaciais do Pleistoceno Médio-Tardio. Diversos estudos têm mostrado que os fenômenos de inserção de regiões mitocondriais no DNA nuclear (NuMts) e heteroplasmia limitam a correta amplificação e identificação dos marcadores mitocondriais. Em estudos filogenéticos e de genética de populações, a presença inadvertida de sequências de diversas origens viola o principio de ortologia, o que pode resultar em inferências evolutivas erradas. Assim, o objetivo do segundo capítulo desta tese foi identificar e caracterizar os possíveis NuMts e sequências heteroplásmicas de três regiões mitocondriais (COI, RC e o gene da subunidade maior do RNA ribossomal: 16S) em quatro espécies do gênero Scyllarides (S. aequinoctialis, S. brasiliensis, S. deceptor e S. delfosi). A clonagem e sequenciamento de extratos de DNA genômico e DNA enriquecido com mtDNA revelaram que os genomas destas espécies podem exibir NuMts (que divergem entre 0,6 e 17,6% do mtDNA) e heteroplasmia (que divergem < 0,2% do mtDNA prevalente). Os NuMts surgiram possivelmente de vários eventos independentes de integração ao núcleo ao longo da história evolutiva do gênero Scyllarides. Dependendo do seu grau de similaridade com o mtDNA, a presença de NuMts nas análises filogenéticas no nível de gênero pode causar superestimativa do número de espécies e alterações nos comprimentos dos ramos e nas relações filogenéticas entre espécies.

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.