From Orders to Borders: Toward a Sustainable Co-managed Lobster Fishery in Bonavista Bay, Newfoundland

Over the last two decades, demands by fish harvesters for greater input into policy-making, combined with government cutbacks to fisheries management agencies, have resulted in a proliferation of community-based fisheries comanagement projects in many countries. One such example is found on Newfoundland’s Eastport Peninsula, where a group of lobster harvesters have formed a unique partnership with federal government bureaucrats and university researchers in an effort to protect local lobster stocks from increasing fishing pressure. This paper draws upon interviews with lobster harvesters and others with close ties to the Eastport project in exploring the reasons for the development of this initiative and identifying existing and potential obstacles to its long-term success.

Comparison of injuries to New Zealand rock lobsters (Jasus edwardsii) caused by hand versus snare collection

Abstract

Following the prohibition in New Zealand of lobster snares in late 2005, we undertook research to compare the frequency and extent of injuries to rock lobsters (Jasus edwardsii) (Hutton) caused by recreational SCUBA divers using lobster snares compared with hand collection. Rock lobsters were sampled between January 2006 and October 2006 from multiple dive sites around the North Island of New Zealand. Of the 124 rock lobsters caught, 20.9% were in a soft shell state. Female rock lobsters constituted 43.5% of the catch, but only one was carrying eggs. Female mean tail width was 72.2 mm; male mean tail width was 71.9 mm. We found that hand collection caused significantly more injuries than snare collection, to both soft shell and hard shell animals. Hand collection also resulted in more major injuries, with 18% of hard shell animals and 31% of soft shell animals losing two or more limbs. We recommend that the prohibition on the use of rock lobster snares be lifted, as their use appears to significantly reduce injury and stress to rock lobsters in recreational dive areas, and increase the survival of undersized individuals released after capture.     

Comparison of the roles of neurohormones in the regulation of blood distribution from the hearts of American and Japanese lobsters

The decapod cardiovascular system consists of a single ventricle that pumps blood into seven arteries; previous work has shown that the outflow distribution patterns of intact animals are variable. In the present study, flow recordings were made from pairs of arteries in semi-isolated hearts whilst different cardioactive hormones were infused into the heart. Each hormone (5-hydroxytryptamine, octopamine, dopamine, proctolin and F1) changed the outflow pattern, heart rate and ventricular pressure in a unique way. The probable sites of hormone action are the cardioarterial valves located at the origin of each artery except one, the dorsal abdominal. Outflow from the dorsal abdominal is controlled downstream by valves located at the origin of the segmental lateral arteries. The responses to a particular hormone were sometimes different between the hearts of American and Japanese lobsters. Accepted: 11 May 1998     

Histopathology of Aerococcus viridans var. homari infection (Gaffkemia) in the lobster, Homarus americanus, and a comparison with histological reactions to a gram-negative species, Pseudomonas perolens

Histological response of lobsters to injection of Aerococcus viridans var. homari, cause of gaffkemia, was followed over a 14-day period. Salient features in infected lobsters, Homarus americanus, were: aggregations of hemocytes occurring in hemal spaces throughout the tissues and increasing in number and size with time; the early phagocytosis of bacteria by the system of fixed phagocytes (FPs) present in hemal spaces of the hepatopancreas; and premature release of differentiating hemocytes from the hemopoietic tissue, so that by 14 days that tissue consisted mainly of large stem cells. Mass release of differentiating hemocytes presumably occurred to replace hemocytes lost from the circulation by their incorporation into aggregations or by lysis of individual cells ruptured through the pressure of phagocytized bacteria that were multiplying in them. Bacteria and their remains were present in FPs at 2 days but not visible in single or aggregated hemocytes until 6 days, when free bacteria were also present in the hemolymph. By 6 days, all bacteria, whether phagocytized or free, appeared normal and were surrounded by nonstaining halos that extended well beyond the stainable capsular material. As predicted earlier in physiological studies, gaffkemia is a nontoxic, noninvasive bacteremia. There was hemal stasis and consequent injury in the antennal gland due to free and aggregated hemocytes that occluded hemal spaces of that organ, but other tissues and organs appeared normal except for depletion of glycogen. Aggregations of hemocytes were present in lobsters 2 and 12 days after injection of a nonpathogenic, Gram-negative bacterium, Pseudomonas perolens. Unlike the case with gaffkemia, necrotic hemocytes were common in the aggregations, presumably in response to damage by endotoxin. A further difference was that aggregations were common in the heart of P. perolens-injected lobsters but rare in the heart of gaffkemic lobsters. Bacteria were not seen in hemolymph, hemocytes, or other cells of P. perolens-injected lobsters.     

Development of Mitochondrial DNA Primers for Use with Homarid Lobsters

DNA primer sets were developed for the amplification of complete mitochondrial genomes for both European and American lobsters in 4 suitable-sized segments. Optimal conditions for polymerase chain reaction routine screening were established. The 4 segments were screened with 24 restriction endonucleases in a test population sample, covering the whole distribution of the European lobster, and restriction patterns of each enzyme were revealed. A segment of 3000 bp comprising part of cytochrome oxidase I gene, the genes cytochrome oxidase II and III, subunits 6 and 8 of ATPase, subunit 3 of the NAD dehydrogenase, and various transfer RNAs, was found to be the most polymorphic. A number of enzyme patterns in each segment differentiated European and American lobsters. Extra bands were observed, indicating heteroplasmy phenomena, which were verified with various approaches. Furthermore, a primer set that enables 1-step ampli- fication of the complete mitochondrial genome of the European lobster was established.     

Synchronous Bursting Can Arise from Mutual Excitation, Even When Individual Cells are not Endogenous Bursters

Mutual excitation between two neurons is generally thought to raise the excitation level of each neuron or, if they are both bursty, to act to synchronize their bursts. If only one is bursty, it can induce synchronized bursts in the other cell. Here we show that two nonbursty cells can be induced to burst in synchrony by mutual excitatory synaptic connections, provided the presynaptic threshold for graded synaptic transmission ateach synapse is at a different level. This mechanism may operate in a recently discovered network in the lobster Homarus gammarus.By a duality between presynaptic threshold and injected current, we also show that two identical, nonbursty, mutual excitatory cells could be induced to burst in synchrony by injecting differing amounts of current inthe two cells. Finally we show that differential oscillations betweentwo mutual excitatory cells could be stopped by a slow-tailedhyperpolarizing current pulse into one cell or a slow-taileddepolarizing pulse into the other.     

Testing the consistency of connectivity patterns for a widely dispersing marine species

Connectivity is widely recognized as an important component in developing effective management and conservation strategies. Although managers are generally most interested in demographic, rather than genetic connectivity, new analytic approaches are able to provide estimates of both demographic and genetic connectivity measures from genetic data. Combining such genetic data with mathematical models represents a powerful approach for accurately determining patterns of population connectivity. Here, we use microsatellite markers to investigate the genetic population structure of the New Zealand Rock Lobster, Jasus edwardsii, which has one of the longest known larval durations of all marine species (>2 years), a very large geographic range (>5500 km), and has been the subject of extensive dispersal modeling. Despite earlier mitochondrial DNA studies finding homogeneous genetic structure, the mathematical model suggests that there are source-sink dynamics for this species. We found evidence of genetic structure in J. edwardsii populations with three distinct genetic groups across New Zealand and a further Australian group; these groups and patterns of gene flow were generally congruent with the earlier mathematical model. Of particular interest was the consistent identification of a self-recruiting population/region from both modeling and genetic approaches. Although there is the potential for selection and harvesting to influence the patterns we observed, we believe oceanographic processes are most likely responsible for the genetic structure observed in J. edwardsii. Our results, using a species at the extreme end of the dispersal spectrum, demonstrate that source-sink population dynamics may still exist for such species.     

Technique for the long-term storage of lobster (Homarus) spermatophores

We have developed a procedure for the long-term storage of lobster (Homarus) sperm. Sperm are collected from males by electrically stimulating the area around the gonopore. They are transferred with a bamboo stick to a plastic test tube containing paraffin oil and are stored for variable periods of time at 4–7°C. Sperm stored up to 289 days appear morphologically normal (equivalent to unstored sperm) when examined by phase contrast microscopy and electron microscopy, and morphologically normal sperm are able to undergo acrosome reactions. After longer periods of storage, degenerative changes begin to develop in sperm. These include loss of the nuclear spikes, condensation of the subacrosomal material, and distortion of the acrosome. Sperm stored better in spermatophores that had thick walls than in those with thin walls. In some spermatophores, bacteria were found in the sperm mass after storage; in general, sperm in these spermatophores were morphologically abnormal. This technique provides a means for saving lobster sperm for subsequent use in experiments or for artificial insemination of female lobsters. It may be adaptable to other invertebrate species that produce spermatophores.     

The reactions of the Norway lobster,Nephrops norvegicus (L.), to water currents

Observations were made on the reactions of the Norway lobster, Nephrops norvegicus, to water currents in a sea‐water flume tank. Blind animals were used to prevent visually‐guided behaviour. Nephrops adopted a downstream orientation, and usually walked downstream, in response to water current speeds in the range of 0.07 to 0.20 ms^?1. Patterns of water flow around the body revealed that it was most effectively streamlined when the animal adopted a downstream orientation. Direct measurements of the forces acting on the body revealed that animals with a downstream orientation experienced the least hydrodynamic drag and the greatest downforce.     

Global gene expression profiling of Homarus americanus (Crustacea) larval stages during development and metamorphosis

Homarus americanus has a life history that is similar to other arthropods, including a pelagic larval phase and a benthic adult phase. The larval phase is divided into three morphologically distinct stages, followed by metamorphosis to the post-larval phase. H. americanus larval development has been studied previously, although the molecular mechanisms that regulate the consequent changes are not fully elucidated. This study is the first to use an oligonucleotide microarray to investigate global gene expression during H. americanus larval development. Stage-specific gene expression profiles of larvae and postlarvae from two-year classes were assessed. We found the expression levels of 1851 genes to be significantly different among larval stages. Functional annotations indicated that various differentially expressed genes were involved with immune function, energy regulation, and development. Ten target genes of interest were selected for expression verification using RT-qPCR. Two Phosphoenolpyruvatecarboxykinases, Argonaute 2, Ecdysone-inducible protein 75, and Procollagen-lysine 2-oxoglutarate 5-dioxygenase 3, had significantly different expression (p?相似文献   

Specificity of odorant-evoked inhibition in lobster olfactory receptor neurons

Lobster olfactory receptor neurons, like those of many animals, use two modes of olfactory signaling, excitation and inhibition to code olfactory information. Inhibition appears to act through two distinct ionic mechanisms. Here we show that neither ionic mechanism is odor-specific, providing further support for the emerging understanding that there are no inhibitory odorants per se, but rather that the action of a particular odorant is inherent in the olfactory receptor cell on which an odorant acts.     

Experimental confirmation of external fertilisation in the southern temperate rock lobster Jasus edwardsii (Hutton) (Decapoda: Palinuridae)

An experimental approach was adopted to clarify whether fertilisation in Jasus, a southern temperate genus of rock or spiny lobster (Decapoda: Palinuridae), occurs internally or externally. Female Jasus edwardsii, isolated from males until they moulted, to ensure that they were unmated, were randomly assigned to treatments in which internal fertilisation was physically prevented or to methodological controls. Examination of eggs attached to setae on the pleopods indicated that those from all females from all treatments had divided and were therefore fertilised. The only mechanism that explains these results is external fertilisation via a spermatophore deposited on the sternal plates of the female during copulation. Because of similar morphologies it is likely that in all Jasus species fertilisation occurs by this external mechanism. These experimental results are important in understanding the mating system of Jasus and in clarifying the phylogenetic relationships of this genus, and suggest that claims for internal fertilisation in related taxonomic groups warrant similar experimental testing before they are accepted.     

The reproductive cycle of Norway lobster

The reproductive biology of female Norway lobster Nephrops norvegicus was studied throughout an annual cycle from January to December 2007 in Pagasitikos Gulf, a large semi-enclosed Gulf in the central west Aegean Sea, in Greece. Six ovarian maturation stages were described to follow gonadal development, based on the combined external observation and histological examination of the ovary. Reproduction showed clear seasonality both in terms of ovarian maturation and brooding period. The proportion of fully mature females in the catch increased from January to the summer months with a peak in June. The species has a protracted brooding period that peaks in November and December, while the release of eggs from females' pleopods occurs from January to March. The size at which 50% of females reached sexual maturity was estimated, using a logistic model, to be 28.1 mm of carapace length. The undiscovered reproductive dynamics will be valuable for optimizing population models and management strategies for this important fishery resource.     

Ten di- and trinucleotide microsatellite loci in the Caribbean spiny lobster, Panulirus argus, for studies of regional population connectivity

We describe 10 microsatellite loci for Panulirus argus (Caribbean spiny lobster). The number of alleles at each locus ranged from four to 39 (mean = 21.8) in 89 juvenile specimens collected at two different times at a recruitment site in south Florida. Levels of expected and observed heterozygosities ranged from 0.48 to 0.96 (mean = 0.83) and from 0.32 to 0.98 (mean = 0.71), respectively. Significant departures from Hardy–Weinberg equilibrium were observed at two loci. There was no evidence of genotypic disequilibrium for any pair of loci. Overall, the loci were well resolved, highly polymorphic and independently segregating, confirming their utility for population genetic studies.     

东方扁虾精子发生的超微结构

应用电镜技术研究了东方扁虾（Thenus orientalis)精子发生的全过程,精原细胞呈椭圆形,其染色质分布较均匀,线粒体集中于细胞一端形成“线粒体区”。初级精母细胞较大,染色质凝聚成块,次级精母细胞核质间常出现大的囊泡,胞质内囊泡丰富而线粒体数量却明显减少,早期精细胞核发生极化、解聚,部分胞质被抛弃。中期精细胞外观呈金字塔形,分为三区;正在形成的顶体位于塔顶,核位于塔基部,居间的细胞质基质内富含膜复合物,后期精细胞顶体进一步分化。形成顶体帽和内、外顶体物质等三个结构组份。成熟精子核呈盘状或碗状,具有5-6条内部充满微管的辐射臂。     

Assay methods for methyl farnesoate esterases in crustaceans

Methyl farnesoate (MF) is a sesquiterpenoid that is synthesized by crustaceans and is structurally similar to the insect juvenile hormones. MF is metabolized to farnesoic acid by carboxylesterases present in crustacean tissues. In order to investigate the biological significance of MF metabolism, we have developed two rapid methods for measuring MF esterase activity. The first method is a radiochemical partition assay that utilizes an authentic substrate. The [³H]MF partition assay was used to evaluate the spectrophotometric esterase substrates methyl 1-heptylthioacetothioate (HEPTAT) and methyl 1-pentylthioacetothioate (PENTAT) for use with crude and partially purified samples of MF esterases from lobster hepatopancreas (midgut gland). The spectrophotometric method is less specific for MF esterases than the partition assay but is less time consuming and nonradioactive, and it provides kinetic information. HEPTAT and PENTAT were suitable for rapid screening of chromatographic fractions for MF esterase activity. Arch. Insect Biochem. Physiol. 36:115–128, 1997. © 1997 Wiley-Liss, Inc.     

Characteristics of palinurids (Decapoda; Crustacea) in larval culture

Complete development of phyllosomas wasaccomplished in Palinurus elephas, Panulirus japonicus, Jasus edwardsii and J. verreauxi. Larval development differsbetween species in duration and moult frequency aswell as morphology. The highest percent survival was obtained during the phyllosoma stage forJ. verreauxi. Phyllosomas of P. elephas were the mostdifficult to cultureregardless of the fact that they hatch at arelatively advanced stage. Culture experiments werecarried out to improve the percent survival of P. elephas. First instars of P. elephasexhibited vigorous predation upon the larvae ofJapanese sandfish Arctoscopus japonicus.Duration of the first instar was shorter at 12.8days when reared at 18 °C and percent survival wasapproximately 30%. Better results were obtainedfor first instars cultured in water inoculated withChaetoceros sp. and fed enriched Artemianauplii. Phyllosomas of J. edwardsii and P. japonicus were cultured without particulardifficulty. Most distinguishing features of P. elephasis the heavily setose six or seven longspines on the distal edges of the scaphognathite ofthe second maxillae while only four long spines arefound in other species. These facts suggest thatphyllosomas of P. elephas are initiallyplankton feeders and from first instar becomerapacious predators.     

Strategies, Conflict, and the Emergence of Territoriality: The Case of the Maine Lobster Industry

In this article, we use game theory to understand the emergence of various kinds of territorial arrangements in the Maine lobster fishery during the past century. Using the Nash equilibria of models of the fishery as our theoretical framework, we show that informal territorial arrangements in this fishery went through three sequential stages. These stages are the result of decisions by groups of lobster fishermen to defend fishing areas or invade those of other groups. A large number of factors influence these defensive and offensive strategies: concentrations of lobsters, the adoption of better technology, transportation costs, ecological changes, trap monitoring costs, the ability to organize defensive and offensive groups, and better law enforcement---all of which are captured by crucial parameters of our model. We argue that this technique can be applied to elucidate territorial changes more generally.     

A complex cortical reaction leads to formation of the fertilization envelope in the lobster,Homarus

We have examined the formation of the fertilization envelope in the lobsters Homarus americanus and H gammarus. Oocytes were fixed for electron microscopy either in the ovary or following extrusion from the gonopore. Mature ovarian oocytes are surrounded by a coat (envelope 1), which is comprised of small electron-dense granules and structures resembling “bottlebrushes.” At least part of this coat is synthesized by the follicle cells of the ovary. The cortex of ovarian oocytes contains four types of vesicles that we refer to as high-density vesicles (HDV), low-density vesicles (LDV), moderately dense vesicles (MDV), and ring vesicles (RV). Oocytes that were electrically extruded from the gonopore and fixed immediately had an envelope identical to that of ovarian oocytes. The cortex of gonopore oocytes contained the four types of vesicles found in ovarian oocytes. When unfertilized gonopore oocytes were allowed to incubate in sea water, the oocyte cortex appeared unaltered, but envelope 1 swelled and the bottlebrushes dispersed. When recently fertilized oocytes were fixed during natural spawning or following in-vitro fertilization, each type of vesicle was released in sequence from the cortex of the oocyte. The contents of the HDV and LDV appeared first in the perivitelline space, but their fate could not be determined at later times. The ring-shaped elements of the RV and the moderately electron-dense material of the MDV were released exocytotically somewhat later; these materials coalesced in the perivitelline space to form a new coat (envelope 2). Envelope 1 subsequently condensed to its original thickness and appeared firmly attached to envelope 2. Our results show that the fertilized lobster egg is surrounded by two discrete coats. The outer coat, which is formed in the ovary, undergoes a swelling/condensation cycle at spawning. The inner coat originates from a complex cortical reaction. Together these coats comprise the fertilization envelope of the lobster egg.     

The lobster fiefs: Economic and ecological effects of territoriality in the maine lobster industry

Lobstermen from each community along the coast of central Maine claim inshore fishing rights in particular areas. Although their claims are unrecognized by the state, they are well established and backed by surreptitious violence. Two kinds of lobstering territories exist, here termed nucleated and perimeterdefended, which differ essentially in the extent to which exclusive fishing rights are maintained. These differences in territorial organization affect the fishing effort of lobstermen, which in turn has a strong biological and economic impact.On leave 1974–1975 to serve with the National Marine Fisheries Service, Washington, D.C.The research on which this paper is based was financed by the National Marine Fisheries Service (Contract No. N-043-30-72) and a Faculty Research Grant from the University of Maine in 1973.