Volunteer-based monitoring of juvenile American lobster, Homarus americanus

2001 ◽  
Vol 52 (8) ◽  
pp. 1103 ◽  
Author(s):  
Sara L. Ellis ◽  
Diane F. Cowan
Keyword(s):  
Carapace Length ◽  
Gulf Of Maine ◽  
Geographical Area ◽  
Monitoring Program ◽  
Work Force ◽  
Cost Effective ◽  
Homarus Americanus ◽  
Primary Objective ◽  
Substrate Temperatures ◽  
Penobscot Bay

The primary objective of the Juvenile Lobster Monitoring Program is to develop a time series of abundance and distribution of juvenile American lobsters. Between 1997 and 2000, trained volunteers quadrat sampled 1-m2 quadrats along fixed 20-m transects monthly from May through October at 24 intertidal sites in the Gulf of Maine. Lobster carapace length ranged from 4 to 82 mm (34.6 0.26 mm, n = 1874). Monthly densities of early benthic phase (≤40 mm CL, EBP) lobsters ranged from 0 to 1.50 lobsters/m2 (0.31 0.010 lobsters/m2, n = 1417). Peak EBP densities coincided with peak substrate temperatures recorded in situ at low tide. Interregionally, EBP density was highest in Massachusetts and lowest in Penobscot Bay, corresponding with relative regional substrate temperatures. Mean lobster carapace length was greater, and EBP density lower, in eelgrass than in rocky habitat. In a 1999 bay-wide survey of Penobscot Bay, Maine, lobsters were detected in outer, but not inner, regions. A strong correlation between abundances at intertidal and subtidal sites (r = 0.86, P< 0.001, n= 17) indicates similar patterns of abundance in the two zones. A volunteer work-force allows cost-effective long-term research on juvenile lobsters over a wide geographical area.

Movements of Tagged American Lobsters, Homarus americanus, off Southwestern Nova Scotia

1985 ◽  
Vol 42 (2) ◽  
pp. 229-238 ◽  
Author(s):  
Alan Campbell ◽  
Aivars B. Stasko
Keyword(s):  
Nova Scotia ◽  
Continental Shelf ◽  
Carapace Length ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Long Distance ◽  
Mature Adults ◽  
Straight Line ◽  
Straight Line Distance ◽  
Long Distance Movement

A total of 4304 American lobsters (Homarus americanus) were tagged and released in inshore areas off southwestern Nova Scotia and on northwest Browns Bank during June–August 1975. Of the 424 lobsters recaptured within 5.4 yr of release, 385 had known recapture locations. For all release areas the average straight-line distance traveled by mature ([Formula: see text]carapace length) lobsters (15.6 km) was significantly greater than for immature (59–94 mm carapace length) lobsters (4.7 km). Most (69.3%) of the immature lobsters (N = 212) were recaptured less than 18.5 km (10 naut mi) from the release sites; for mature lobsters (N = 173) this percentage was 40.5%. Previous tagging studies off southwestern Nova Scotia revealed little evidence of long-distance movement; our study, however, shows that mature lobsters can move long distances. Many (19.7%) of the mature lobsters were recaptured more than 92.6 km (50 naut mi) from the release sites. The overall direction of travel was south, in both an east and west direction, with many lobsters moving greater than 50 km from coastal Nova Scotia and Browns Bank into the Gulf of Maine and to the slopes of the continental shelf. Thirteen lobsters moved from Browns Bank to inshore areas of southwestern Nova Scotia. The evidence of the long-distance interchange of a portion of the mature adults between southwestern Nova Scotia and the adjoining continental shelf suggests that lobsters in these areas could belong to a single stock.

Large-scale and long-term, spatial and temporal patterns in demography and landings of the American lobster, Homarus americanus, in Maine

2001 ◽  
Vol 52 (8) ◽  
pp. 1303 ◽  
Author(s):  
Robert S. Steneck ◽  
Carl J. Wilson
Keyword(s):  
Gulf Of Maine ◽  
Temporal Patterns ◽  
Homarus Americanus ◽  
American Lobster ◽  
Cold Spot ◽  
Spatial And Temporal Patterns ◽  
Population Densities ◽  
North East ◽  
Catch Rates ◽  
Penobscot Bay

The American lobster, Homarus americanus, is abundant (>1/m2) in spatially complex coastal habitats of the Gulf of Maine. Quadrat surveys (stratified by exposure, depth, and substrate) conducted at fixed locations since 1989 revealed consistently higher lobster population densities west and south of Penobscot Bay in central Maine. High-resolution surveys in 1999 at 70 closely spaced dive sites revealed distinct settlement hot spots and cold spots, stable over several years at least. Densest settlement occurred along a 100-km outer coastal region westward from the mouth of Penobscot Bay. A settlement cold spot about 60-km in diameter was evident in the north-east corner of Penobscot Bay. Abundance of older, adolescent-phase, lobsters (40–90 mm carapace length, CL) corresponded with patterns of settlement. Catch rates per trap haul of prerecruits (< 83 mm CL) and catch rates per area for lobsters fully recruited to the fishery (83 mm CL) correspond with local lobster densities. Until recently, populations increased in three of four regions over the past decade, most strongly in north-eastern Maine. Landings per length of coastline corresponded to spatial and temporal patterns of abundance. Consistent spatial and temporal patterns suggest that population densities can be reliably determined from calibrated fisherydependent data.

Predicting bycatch hotspots based on suitable habitat derived from fishery-independent data

2020 ◽  
Vol 641 ◽  
pp. 159-175
Author(s):  
J Runnebaum ◽  
KR Tanaka ◽  
L Guan ◽  
J Cao ◽  
L O’Brien ◽  
...  
Keyword(s):  
Habitat Suitability ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Management Tool ◽  
American Lobster ◽  
Suitable Habitat ◽  
Climate Conditions ◽  
Suitability Index

Bycatch remains a global problem in managing sustainable fisheries. A critical aspect of management is understanding the timing and spatial extent of bycatch. Fisheries management often relies on observed bycatch data, which are not always available due to a lack of reporting or observer coverage. Alternatively, analyzing the overlap in suitable habitat for the target and non-target species can provide a spatial management tool to understand where bycatch interactions are likely to occur. Potential bycatch hotspots based on suitable habitat were predicted for cusk Brosme brosme incidentally caught in the Gulf of Maine American lobster Homarus americanus fishery. Data from multiple fisheries-independent surveys were combined in a delta-generalized linear mixed model to generate spatially explicit density estimates for use in an independent habitat suitability index. The habitat suitability indices for American lobster and cusk were then compared to predict potential bycatch hotspot locations. Suitable habitat for American lobster has increased between 1980 and 2013 while suitable habitat for cusk decreased throughout most of the Gulf of Maine, except for Georges Basin and the Great South Channel. The proportion of overlap in suitable habitat varied interannually but decreased slightly in the spring and remained relatively stable in the fall over the time series. As Gulf of Maine temperatures continue to increase, the interactions between American lobster and cusk are predicted to decline as cusk habitat continues to constrict. This framework can contribute to fisheries managers’ understanding of changes in habitat overlap as climate conditions continue to change and alter where bycatch interactions could occur.

Multiple Fertilization and Consecutive Spawning in Large American Lobsters, Homarus americanus

1986 ◽  
Vol 43 (11) ◽  
pp. 2291-2294 ◽  
Author(s):  
S. L. Waddy ◽  
D. E. Aiken
Keyword(s):  
Body Size ◽  
Carapace Length ◽  
Homarus Americanus ◽  
Large Female ◽  
Bay Of Fundy ◽  
Relative Fecundity ◽  
Logarithmic Relationship

Large female American lobsters, Homarus americanus (> 120 mm carapace length), maintained at nearshore Bay of Fundy temperatures often spawn twice without an intervening molt (consecutive spawning). Consecutive spawning occurs in two forms: successive-year (spawning in two successive summers, a molt in the first and fourth years) and alternate-year (spawning in alternate summers, a molt in the first and fifth years). In both types, females often are able to fertilize the two successive broods with the sperm from a single insemination (multiple fertilization). Twenty of 21 large females that were held for up to 13 yr displayed one of these types of consecutive spawning. Consecutive spawning and multiple fertilization enable large lobsters to spawn more frequently over the long term than their smaller counterparts. This, combined with the logarithmic relationship between body size and numbers of eggs produced, means that very large lobsters have a much greater relative fecundity than previously thought.

Size–Maturity Relationships and Related Observations in Newfoundland Populations of the Lobster (Homarus americanus)

1980 ◽  
Vol 37 (6) ◽  
pp. 945-956 ◽  
Author(s):  
G. P. Ennis
Keyword(s):  
Carapace Length ◽  
Size Range ◽  
Sex Ratios ◽  
Weight Ratio ◽  
Homarus Americanus ◽  
Spawning Season ◽  
Length Ratio ◽  
Maturity Indices

Female maturity ogives for five Newfoundland populations of the lobster (Homarus americanus) gave 50% maturities ranging from 71- to 76-mm carapace length. Sizes at which distinct inflections (indicating onset of maturity) and asymptotes (indicating 100% mature) are present in the abdomen width/carapace length ratio vs. carapace length relationships coincide with the smallest ovigerous and largest immature specimens, respectively, observed in those particular samples. Inflection in the crusher claw weight/whole weight ratio vs. carapace length relationships (used in this paper to indicate onset of maturity in males) occurred at larger sizes than inflections in the abdomen width/carapace length ratios of females.The percentage of nonovigerous females that spawn in a given year generally increases with increasing size. The highest percentage of nonovigerous females tagged with sphyrion tags prior to the spawning season that were ovigerous when recaptured 10–12 mo later was 83.8%. The percentage of ovigerous females with new shells (i.e. molted and spawned in same year) varied between areas and years and ranged from 0 to 38.5% of the total number of ovigerous females in fall samples. The percentage of ovigerous females in samples also varied between areas and years and ranged from 2.6 to 30.4% of the total number of females greater than the size at 50% maturity. In general a greater percentage of females was ovigerous at sizes between the size at 50% maturity and 80 mm (largest subcommercial size) than at commercial sizes.In a sample of nonovigerous females, the size range at which 50% were fertilized (76–80 mm) coincided closely with the size at 50% maturity (75 mm) for the area.At subcommercial sizes (< 81 mm) the sexes were approximately equally represented in fall trap-caught samples but females heavily outnumbered males in diver-caught samples taken over the same period. At commercial sizes, however, males heavily outnumbered females in the trap-caught samples while in diver-caught samples the sexes were equally represented.Key words: lobster (Homarus americanus), maturity ogives, maturity indices, percent ovigerous, sex ratios

Larval lobster (Homarus americanus) distribution and drift in the vicinity of the Gulf of Maine offshore banks and their probable origins

2005 ◽  
Vol 14 (2) ◽  
pp. 112-137 ◽  
Author(s):  
G. C. HARDING ◽  
K. F. DRINKWATER ◽  
C. G. HANNAH ◽  
J. D. PRINGLE ◽  
J. PRENA ◽  
...  
Keyword(s):  
Gulf Of Maine ◽  
Homarus Americanus

Advancing an Ecosystem Approach in the Gulf of Maine

2012 ◽  
Keyword(s):  
Large Scale ◽  
Gulf Of Maine ◽  
Critical Role ◽  
Monitoring Program ◽  
Ecosystem Dynamics ◽  
Georges Bank ◽  
Scotian Shelf ◽  
Monitoring Programs ◽  
Zooplankton Dynamics ◽  
Biological Environment

<i>Abstract</i>.—Zooplankton communities perform a critical role as secondary producers in marine ecosystems. They are vulnerable to climate-induced changes in the marine environment, including temperature, stratification, and circulation, but the effects of these changes are difficult to discern without sustained ocean monitoring. The physical, chemical, and biological environment of the Gulf of Maine, including Georges Bank, is strongly influenced by inflow from the Scotian Shelf and through the Northeast Channel, and thus observations both in the Gulf of Maine and in upstream regions are necessary to understand plankton variability and change in the Gulf of Maine. Large-scale, quasi synoptic plankton surveys have been performed in the Gulf of Maine since Bigelow’s work at the beginning of the 20th century. More recently, ongoing plankton monitoring efforts include Continuous Plankton Recorder sampling in the Gulf of Maine and on the Scotian Shelf, U.S. National Marine Fisheries Service’s MARMAP (Marine Resources Monitoring, Assessment, and Prediction) and EcoMon (Ecosystem Monitoring) programs sampling the northeast U.S. Continental Shelf, including the Gulf of Maine, and Fisheries and Oceans Canada’s Atlantic Zone Monitoring Program on the Scotian Shelf and in the eastern Gulf of Maine. Here, we review and compare past and ongoing zooplankton monitoring programs in the Gulf of Maine region, including Georges Bank and the western Scotian Shelf, to facilitate retrospective analysis and broadscale synthesis of zooplankton dynamics in the Gulf of Maine. Additional sustained sampling at greater-than-monthly frequency at selected sites in the Gulf of Maine would be necessary to detect changes in phenology (i.e. seasonal timing of biological events). Sustained zooplankton sampling in critical nearshore fish habitats and in key feeding areas for upper trophic level organisms, such as marine mammals and seabirds, would yield significant insights into their dynamics. The ecosystem dynamics of the Gulf of Maine are strongly influenced by large-scale forcing and variability in upstream inflow. Improved coordination of sampling and data analysis among monitoring programs, effective data management, and use of multiple modeling approaches will all enhance the mechanistic understanding of the structure and function of the Gulf of Maine pelagic ecosystem.

Supply Chains of Commodity Products in India

2012 ◽  
pp. 97-115
Author(s):  
Deepti Dewani ◽  
Shreyansh Jain ◽  
Sumeet Gupta
Keyword(s):  
Supply Chain ◽  
Distribution System ◽  
Geographical Area ◽  
Cost Effective ◽  
The Poor ◽  
Marketing Season ◽  
Agricultural Societies ◽  
Typical Distribution ◽  
Management Techniques ◽  
The Government

Rice is one of the major commodities produced and consumed in India. India is also home to one of the finest varieties of rice sold under the name of Basmati. The State of Chhattisgarh is considered the Rice Bowl of India as it is one of the largest contributors to paddy production in India. Around 3 million families subsist on farming in Chhattisgarh, out of which, 1.522 million families are small farmers (owning less than 2 hectares of land). The Government of Chhattisgarh procures paddy in Chhattisgarh on behalf of Government of India. This scheme benefits about 1 million farmer families by procuring about 3 million metric tons of paddy in the Kharif Marketing Season (KMS) of a year, spending about 600 Million US Dollars. The procurement takes place through about 1333 Primary Agricultural Societies in the whole state covering geographical area of 135000 sq. km. The paddy procured is converted into rice by millers after entering into an agreement. Rice is then handed over to Chhattisgarh State Civil Supplies Corporation to use it in another important scheme for providing food security to the poor. The supply chain of rice production is very simple. It is harvested in the form of paddy from the field and sold to the millers who then process the rice. The processed rice is then sold to the market. Although simple, there are a number of inefficiencies present in its supply chain. This case familiarizes the readers of the distribution system of rice, various government policies in its distribution system, and the issues that need to be addressed in a typical distribution system of rice. The case also urges the readers to mull over how these inefficiencies can be overcome with the latest supply chain management techniques so as to make its distribution efficient and cost effective.

scholarly journals Paralytic Shellfish Toxins in Surf Clams Mesodesma donacium during a Large Bloom of Alexandrium catenella Dinoflagellates Associated to an Intense Shellfish Mass Mortality

Toxins ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 188 ◽  
Author(s):  
Gonzalo Álvarez ◽  
Patricio Díaz ◽  
Marcos Godoy ◽  
Michael Araya ◽  
Iranzu Ganuza ◽  
...  
Keyword(s):  
Digestive Gland ◽  
Harmful Algal Bloom ◽  
Geographical Area ◽  
Monitoring Program ◽  
Adductor Muscle ◽  
Shellfish Poisoning ◽  
Alexandrium Catenella ◽  
Surf Clam ◽  
Paralytic Shellfish ◽  
Psp Toxins

In late February 2016, a harmful algal bloom (HAB) of Alexandrium catenella was detected in southern Chiloé, leading to the banning of shellfish harvesting in an extended geographical area (~500 km). On April 24, 2016, this bloom produced a massive beaching (an accumulation on the beach surface of dead or impaired organisms which were drifted ashore) of surf clams Mesodesma donacium in Cucao Bay, Chiloé. To determine the effect of paralytic shellfish poisoning (PSP) toxins in M. donacium, samples were taken from Cucao during the third massive beaching detected on May 3, 2016. Whole tissue toxicity evidence a high interindividual variability with values which ranged from 1008 to 8763 μg STX eq 100 g−1 and with a toxin profile dominated by GTX3, GTX1, GTX2, GTX4, and neoSTX. Individuals were dissected into digestive gland (DG), foot (FT), adductor muscle (MU), and other body fractions (OBF), and histopathological and toxin analyses were carried out on the obtained fractions. Some pathological conditions were observed in gill and digestive gland of 40–50% of the individuals that correspond to hemocyte aggregation and haemocytic infiltration, respectively. The most toxic tissue was DG (2221 μg STX eq 100 g−1), followed by OBF (710 μg STX eq 100 g−1), FT (297 μg STX eq 100 g−1), and MU (314 μg STX eq 100 g−1). The observed surf clam mortality seems to have been mainly due to the desiccation caused by the incapability of the clams to burrow. Considering the available information of the monitoring program and taking into account that this episode was the first detected along the open coast of the Pacific Ocean in southern Chiloé, it is very likely that the M. donacium population from Cucao Bay has not had a recurrent exposition to A. catenella and, consequently, that it has not been subjected to high selective pressure for PSP resistance. However, more research is needed to determine the effects of PSP toxins on behavioral and physiological responses, nerve sensitivity, and genetic/molecular basis for the resistance or sensitivity of M. donacium.

scholarly journals On fitting paradigms to people

1982 ◽  
Vol 13 (4) ◽  
pp. 189-196 ◽  
Author(s):  
A. P. Moerdyk ◽  
David A.L. Coldwell
Keyword(s):  
South Africa ◽  
Work Environment ◽  
Cultural Differences ◽  
Labour Force ◽  
Work Force ◽  
Cost Effective ◽  
Cultural Factors ◽  
Work Place ◽  
Value Structures ◽  
The Individual

In a previous article (Coldwell and Moerdyk, 1981) it was argued that many blacks in South Africa are at a disadvantage in the 'White man's world' of business and industry as a result of a number of cultural factors, some of which were described. In this paper, the suggestion is made that it is probably easier and more cost-effective to find ways in which both tasks and organizations can be restructured along socio-technical design lines, than it is to try to change the personality and value structures of the labour force to fit them to the demands of the work place. A number of cultural differences are outlined and suggestions put forward about possible ways in which jobs and organizations can be modified to make them more compatible with the characteristics of the work force. A closer 'match' between the individual and his work environment is seen as the key to enhanced productivity, reduced stress, and consequent improvements in both job satisfaction and company profitability.

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