Report on the biology of Pacific hagfish, Eptatretus stouti and the development of its fishery in California

Hagfish, often referred to as "slime eels", are familiar to most fishermen as pests that frequently devour fish caught by trap, hook, and gillnet. In the Republic of Korea (ROK or South Korea), however, hagfish are sought after as valuable fish not only for their edible flesh, but also for their skin, which is processed into leather used to make expensive purses, shoes, and other articles. In fact, because of a shortage of hagfish in the waters near the ROK, the leather industry there has started to import hagfish, first from Japan in the mid 1980's, then from the United States starting in 1988. This report describes the nascent fishery for Eptatretus stouti (Pacific hagfish) in California, and includes aspects of its life history. The hagfish industry in the ROK is also briefly described.

Sexual Reproduction and Early Development in the Estuarine Sea Anemone, Nematostella vectensis Stephenson, 1935

This dissertation: 1) determines the factor(s) responsible for spawning induction in NematosteJla vectensis; 2) isolates, describes, and documents the source of jelly from egg masses of N. vectensis; and 3) describes N. vectensis' early development. Namatostella vectensis were maintained on a 7-day mussel feeding/water change regime over 159 days. Within 36 hours of mussel feeding/water change. 69.1% of females and 78.5% of males spawned reliably. Through manipulation of feeding, water change, oxygen and nitrogenous waste concentrations, spawning induction was found to be triggered by the oxygen concentration associated with water change, and not by feeding. Ammonia, anemones' major waste product, inhibited this induction in a concentration-dependent manner. Female N. vectensis release eggs in a persistent jellied egg mass which is unique among the Actiniaria. The major component of this egg mass jelly was a positive periodic acid-Schiffs staining, 39.5-40.5 kD glycoprotein. Antibodies developed in rabbits against this glycoprotein bound to jelly of intact egg masses and to granules (~ 2.8 IJm in diameter) present in female anemone mesenteries and their associated filaments. Antibodies did not label male tissues. Nematostella vecfensis embryos underwent first karyokinesis -60 minutes following the addition of sperm to eggs. Second nuclear division took place, followed by first cleavage, 90-120 minutes later. Each of the 4 blastomeres that resulted from first cleavage contained a single nucleus. Arrangement of these blastomeres ranged from radial to pseudospiral. Embryonic development was both asynchronous and holoblastic. Following formation of the 4-cell stage, 71% of embryos proceeded to cleave again to form an 8-cell stage. In each of the remaining 29% of embryos, a fusion of from 2-4 blastomeres resulted in 4 possible patterns which had no affect on either cleavage interval timing or subsequent development. The fusion event was not due to ooplasmic segregation. Blastomeres isolated from 4-celled embryos were regulative and developed into normal planula larvae and juvenile anemones that were 1/4 the size of those that developed from intact 4-celled embryos. Embryos exhibiting the fusion phenomenon were examined at the fine structural level. The fusion phenomenon resulted in formation of a secondary syncytium and was not a mere compaction of blastomeres.

New and innovative advances in biology/engineering with potential for use in aquaculture: Proceedings of the Fourteenth U.S.-Japan Meeting on Aquaculture, Woods Hole, Massachusetts, October 16-17, 1985

The United States and Japanese counterpart panels on aquaculture were formed in 1969 under the United States-Japan Cooperative Program in Natural Resources (UJNR). The panels currently include specialists drawn from the federal departments most concerned with aquaculture. Charged with exploring and developing bilateral cooperation, the panels have focused their efforts on exchanging information related to aquaculture which could be of benefit to both countries. The UJNR was begun during the Third Cabinet-Level Meeting of the Joint United States-Japan Committee on Trade and Economic Affairs in January 1964. In addition to aquaculture, current subjects in the program include desalination of seawater, toxic microorganisms, air pollution, energy, forage crops, national park management, mycoplasmosis, wind and seismic effects, protein resources, forestry, and several joint panels and committees in marine resources research, development, and utilization. Accomplishments include: Increased communication and cooperation among technical specialists; exchanges of information, data, and research findings; annual meetings of the panels, a policy-coordinative body; administrative staff meetings; exchanges of equipment, materials, and samples; several major technical conferences; and beneficial effects on international relations. (PDF file contains 76 pages.)

Development of hexagrammids (Pisces: Scorpaeniformes) in the northeastern Pacific Ocean

Larvae of Oxylebius pictus, Zaniolepis sp., Ophiodon elongatus, Hexagrommos stelleri, H. decagrammus, H. lagocephalus, H. octogrammus, and Pleurogrammus monopterygius are described and illustrated from field collections which were supplemented by laboratory reared specimens of some species. Larvae hatch at a rather large size (3-9 mm), are heavily pigmented, and undergo direct development to an epipelagic prejuvenile stage. Larvae or the five genera are separable on the basis of body shape, pigmentation, and meristic characters. Larvae or the four species of Hexagrammos, which are quite similar in appearance, are separable on the basis of a combination of several pigmentation characters. Developmental evidence indicates that Oxylebius and Zaniolepis are similar to each other and are more similar to presumed primitive coUids than the other included genera. Ophiodon is dissimilar to the other four genera. Pleurogrammus and Hexagrommos have similar appearing larvae. Among the species of Hexagrammos a progression or increasing larval pigmentation can be seen from H. stelleri to H. decagrammus, H. lagocephalus, and H. octogrammus. (PDF file contains 50 pages.)

Underwater Passive Acoustic Monitoring for Remote Regions, Hawaii Institute of Marine Biology, Coconut Island, Hawaii, February 7-9, 2007: workshop proceedings

The Alliance for Coastal Technologies (ACT) convened a workshop, sponsored by the Hawaii-Pacific and Alaska Regional Partners, entitled Underwater Passive Acoustic Monitoring for Remote Regions at the Hawaii Institute of Marine Biology from February 7-9, 2007. The workshop was designed to summarize existing passive acoustic technologies and their uses, as well as to make strategic recommendations for future development and collaborative programs that use passive acoustic tools for scientific investigation and resource management. The workshop was attended by 29 people representing three sectors: research scientists, resource managers, and technology developers. The majority of passive acoustic tools are being developed by individual scientists for specific applications and few tools are available commercially. Most scientists are developing hydrophone-based systems to listen for species-specific information on fish or cetaceans; a few scientists are listening for biological indicators of ecosystem health. Resource managers are interested in passive acoustics primarily for vessel detection in remote protected areas and secondarily to obtain biological and ecological information. The military has been monitoring with hydrophones for decades;however, data and signal processing software has not been readily available to the scientific community, and future collaboration is greatly needed. The challenges that impede future development of passive acoustics are surmountable with greater collaboration. Hardware exists and is accessible; the limits are in the software and in the interpretation of sounds and their correlation with ecological events. Collaboration with the military and the private companies it contracts will assist scientists and managers with obtaining and developing software and data analysis tools. Collaborative proposals among scientists to receive larger pools of money for exploratory acoustic science will further develop the ability to correlate noise with ecological activities. The existing technologies and data analysis are adequate to meet resource managers' needs for vessel detection. However, collaboration is needed among resource managers to prepare large-scale programs that include centralized processing in an effort to address the lack of local capacity within management agencies to analyze and interpret the data. Workshop participants suggested that ACT might facilitate such collaborations through its website and by providing recommendations to key agencies and programs, such as DOD, NOAA, and I00s. There is a need to standardize data formats and archive acoustic environmental data at the national and international levels. Specifically, there is a need for local training and primers for public education, as well as by pilot demonstration projects, perhaps in conjunction with National Marine Sanctuaries. Passive acoustic technologies should be implemented immediately to address vessel monitoring needs. Ecological and health monitoring applications should be developed as vessel monitoring programs provide additional data and opportunities for more exploratory research. Passive acoustic monitoring should also be correlated with water quality monitoring to ease integration into long-term monitoring programs, such as the ocean observing systems. [PDF contains 52 pages]

The shape of fisheries to come. Some thoughts on fisheries development and education with special reference to aquaculture

A brief discussion is presented on the current situation regarding world fisheries and the future role of aquaculture. The various components involved in fisheries, and affecting all changes in fisheries through time, include the biology of the species involved, environment, technology/engineering and socio-economics. The importance of education in fisheries and aquaculture development is also examined

Embryonic development in Clarias gariepinus under laboratory conditions

The embryonic development in Clarias gariepinus was studied under laboratory conditions. The developmental stages of eggs starting from first cleavage were examined microscopically. Photomicroscope was used to take important stages of segmentation, blastulation, differentiation of embryo and hatching. The films of the photograph were developed and printed for each stage produced. The accurate timing and detailed description of each stage was done. The results show that the blastodisc (Polar cap) appeared about 35 minutes after fertilization and the first cleavage dividing the blastodisc into two blastomeres occurs 15 minutes after polar cap formation. Details of the developmental stages of embryos and the timing from one stage to the other were described. The larva shook off the shell and emerged completely from the egg case about 22 hours after fertilization at a water temperature of 25.1 degree C. The accurate determination of the time of initiation of first mitosis is of great importance in fish culture and breeding especially in the production of tetraploids

Potential for sustainable floodplain fisheries development: a case study of Tatabu floodplain

This study presents evidence from a case study of an ecological appraisal of Tatabu flood plain aimed at formulation management approaches for the enhancement of the fishing communities social economic and cultural realities. Tabtabu flood plain is located north of Jebba and at high water the ecosystems cover about 700 hectares. Fishing constitutes the principal economic activity of natural fish food and flora (especially phytoplankton and zooplankton) which support and favour the growth of over 26 fish species that belong to 15 families. Among the commercially important species in terms of dominance on percentage weight basis are Mochokidae, Cichlidae, Claridae and Characidae with an overall average standing crop of 88.24kg/ha based on gill net experiment. The study based on the intrinsic ecological attributes and local people willingness for sustained contribution of fisheries to food supply indicates that with adequate management Tatabu flood plain ecosystems have tremendous fishery potentials that would enhance the economic well being of the communities. Several management options that are applicable to similar plain are discussed

Environmental oestrogens and sexual development in fish

This brief paper discusses the assumption that watercourses might be harbouring a chemical(s) affecting the sexual development in fish. Male fish was found with the oestrogen-dependent blood protein, vitellogenin, usually found only in maturing females. The author examines a number of man-made chemicals present in the environment have been found to be oestrogenic. The paper concludes that rivers contain environmental oestrogens that are capable of causing disruptions in the sexual development of fish. Whether or not these environmental oestrogens are causing a widespread disruption in reproduction in wild fish, however, has yet to be determined.

The development of freshwater science in Britain, and British contributions abroad, 1900-2000

This article outlines the development of freshwater science between 1900 and 2000 and in particular traces British contributions, both to a deepened knowledge of specifics and to their interrelation as environmental and ecological science. The author provides a selected bibliography of important publications relevant to the topic of the article.

The influence of blue-green algae on development of the zooplankton. [Translation of: Byull.mosk.Obshch.Ispyt.Prir.(Biol.) 67, 128-131, 1962]

Many have observed the reduction of the quantity of zooplankton in the presence of water blooms. It is known that in seas zooplankton as it were avoids places of accumulation of blue-green algae. By observations on one of the tributaries of the Rybinsk reservoir - the River Shumorovka - the authors tried by simultaneous collections to trace the changes in numbers, not only of zoo- and phytoplankton but also of bacteria. The plankton was collected by quantitative nets with suitable numbers of gauze and bacteria were taken account of by the method of direct calculation on membrane filters. It can be seen that the development of blue-green algae appears as an important factor, determining not only the intensity but also the direction of the process of production of zooplankton.

The temperature dependence of the development of the embryo in Mesocyclops leuckarti (Claus) and Cyclops scutifer

This work is mainly intended as an addition to the studies of the populations dynamics of Cyclops scutifer, which is part of the ”Latn ja jaure project” (a study of the principles involved in the ecosystem of a small -initially fish free- mountain lake, before and after the introduction of fish). The field work consisted of sampling in Lake Erken in Roslagen in June, July and September, as well as in Latn ja jaure in the Abisko mountains in August and September of 1965. Additional sampling was done in Latn ja jaure for the study of the horizontal, vertical and temporal distribution of Cyclops scutifer, as well as the in situ development of the different stages. These samples have been analysed in such a way as to fit into the frame work of future studies on the population dynamics of Cyclops scutifer, The main aim of the present investigation is the determination of the dependence upon tempera- tare of the development of the embryo in the subarctic Cyclops scutifer as compared with the conditions found in the warm water species Mesocyclops leuckarti.

Significance of the photoperiod for the development of Cyclops vicinus. [Translation from: Zoologischer Anzeiger Supplementband 33, 190-195, 1969.]

The significance of the photoperiod, a well-known phenomenon with arthropods, for the development of Cyclops vicinus were studied in laboratory conditions. There are indications that the point of the development process (development of the eggs and proportion of sexes) can be influenced through the photoperiod.

Observations on the influence of external factors on the duration of the embryonic development and on the molting rhythm of Cyclops vicinus. [Translation from: Oecologia 7, 342-355, 1971.]

Investigations on the control of the embryonic and post-embryonic development of arthropods have formed an intensively studied field of zoological research for a long time, Here in especially favourable cases the causal chain from the operation of external factors on the influence of physiological mechanisms, eg. of the hormone variety, is known right through to its primary influences. A comparative approach to the relevant questions was in the main only made in the case of the insects. For crustacea , investigations are available almost exclusively only for the malacostraca. This study examines the influence of the factors of temperature and photoperiod on the entire development of Cyclops vicinus. Tests were made on whether the light-darkness change serves as a regulator for a possible existing molting rhythm - a question which for the entire arthropods has been settled only very rarely. The basic material for the cultures that were examined originates from Lake Constance.