Spatial surface temperature correlates of American lobster (Homarus americanus) settlement in the Gulf of Maine and southern New England shelf

2018 ◽  
Vol 94 (3) ◽  
pp. 737-751 ◽  
Author(s):  
Mahima Jaini ◽  
Richard A Wahle ◽  
Andrew C Thomas ◽  
Ryan Weatherbee
Keyword(s):  
Surface Temperature ◽  
New England ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
American Lobster ◽  
Southern New England

scholarly journals American lobster nurseries of southern New England receding in the face of climate change

2015 ◽  
Vol 72 (suppl_1) ◽  
pp. i69-i78 ◽  
Author(s):  
Richard A. Wahle ◽  
Lanny Dellinger ◽  
Scott Olszewski ◽  
Phoebe Jekielek
Keyword(s):  
New England ◽  
Rhode Island ◽  
Size Composition ◽  
Homarus Americanus ◽  
Warming Trend ◽  
Shore Crab ◽  
American Lobster ◽  
Southern New England ◽  
Study Sites ◽  
Outer Coast

Abstract Historically, southern New England has supported one of the most productive American lobster (Homarus americanus) fisheries of the northeast United States. Recently, the region has seen dramatic declines in lobster populations coincident with a trend of increasingly stressful summer warmth and shell disease. We report significant declines in the abundance, distribution, and size composition of juvenile lobsters that have accompanied the warming trend in Narragansett Bay, Rhode Island, since the first comprehensive survey of lobster nurseries conducted there in 1990. We used diver-based visual surveys and suction sampling in 1990, 2011, and 2012, supplemented by post-larval collectors in 2011 and 2012. In 1990, lobster nurseries extended from the outer coast into the mid-sections of the bay, but by 2011 and 2012 they were largely restricted to the outer coast and deeper water at the mouth of the bay. Among five new study sites selected by the lobster fishing industry for the 2011 and 2012 surveys, the deepest site on the outer coast (15–17 m depth) harboured some of the highest lobster densities in the survey. Separate fixed site hydrographic monitoring at 13 locations in the bay by the Rhode Island Division of Fish and Wildlife recorded an approximately 2.0°C increase in summer surface temperatures over the period, with 2012 being the warmest on record. Additional monitoring of bottom temperatures, dissolved oxygen and pH at our sampling sites in 2011 and 2012 indicated conditions falling below physiological optima for lobsters during summer. The invasion of the Asian shore crab, Hemigrapsus sanguineus, since the 1990s may also be contributing to declines of juvenile lobster shallow zones (<5 m) in this region. Because lobster populations appear increasingly restricted to deeper and outer coastal waters of southern New England, further monitoring of settlement and nursery habitat in deep water is warranted.

Discrimination of American lobster (Homarus americanus) stocks off southern New England on the basis of secondary sex character allometry

1995 ◽  
Vol 52 (12) ◽  
pp. 2712-2723 ◽  
Author(s):  
Steven X. Cadrin
Keyword(s):  
New England ◽  
Principal Components ◽  
Principal Component ◽  
Homarus Americanus ◽  
American Lobster ◽  
Multiple Group ◽  
Southern New England ◽  
Female Data ◽  
Components Analysis ◽  
Component Scores

Male American lobster (Homarus americanus) from inshore southern New England were discriminated from offshore males on the basis of larger relative chela size. Lobsters from Buzzards Bay (inshore) had more conspicuous sexual dimorphism than lobsters from Hydrographer Canyon (offshore), and allometric growth of male chelae was more prominent than that of female abdomens. Principal components analysis of males from combined stocks represented variability in multivariate size and relative chela size, and component score distributions of each stock were discrete. Principal components of females from both stocks comprised variability in overall size and relative abdomen size, but principal component scores overlapped extensively. Multiple-group principal component 2 was a size-free index of relative chela size that classified 96% of males to the correct stock. Multiple-group principal component 2 of females did not successfully separate stocks. Discriminant analysis of size-adjusted morphometric data classified males to stock with 100% accuracy on the basis of relative chela size. Although discrimination of size-adjusted female data classified stocks with 94% accuracy, it was less stable and not associated with onset of maturity.

Age-at-size relationships of the American lobster (Homarus americanus) from three contrasting thermal regimes using gastric mill band counts as a direct aging technique

2020 ◽  
Vol 77 (10) ◽  
pp. 1733-1740
Author(s):  
Carl J. Huntsberger ◽  
Raouf Kilada ◽  
William G. Ambrose ◽  
Richard A. Wahle
Keyword(s):  
New England ◽  
Gulf Of Maine ◽  
Age Determination ◽  
Homarus Americanus ◽  
Gastric Mill ◽  
Band Formation ◽  
Southern New England ◽  
Thermal Regimes ◽  
The One

Direct age determination of crustaceans has remained a long-standing challenge because all calcified structures are shed with each molt. Cuticle bands in the ossicles of the gastric mill have shown promise as age indicators. We validated the one-to-one relationship between known age and number of cuticle bands for 15 hatchery-raised juvenile American lobsters (Homarus americanus). Additionally, we applied this method to 308 lobsters from three contrasting thermal regimes in New England, USA. Band counts matched our expectations of differences in age-at-size across this thermal gradient; lobsters at harvestable size in southern New England were estimated to be 5.5 (±1.5) years old compared with 7.5 (±1.6) years in the Gulf of Maine. We found 81% of our band count estimates of age fell within 2 years of independent, regionally specified growth model estimates of age-at-size for lobster. Notwithstanding remaining uncertainties regarding the mechanism of band formation, our findings indicate the method may provide an independent and direct means to determine the age of individual American lobsters, which will improve estimates of essential life history parameters.

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.

scholarly journals Developing and evaluating harvest control rules with different biological reference points for the American lobster (Homarus americanus) fishery in the Gulf of Maine

2011 ◽  
Vol 68 (7) ◽  
pp. 1511-1524 ◽  
Author(s):  
Yuying Zhang ◽  
Yong Chen ◽  
Carl Wilson
Keyword(s):  
Gulf Of Maine ◽  
Homarus Americanus ◽  
The United States ◽  
Reference Points ◽  
Systematic Evaluation ◽  
American Lobster ◽  
Natural Mortality ◽  
Control Rules ◽  
The Status ◽  
Harvest Control Rules

Abstract Zhang, Y., Chen, Y., and Wilson, C. 2011. Developing and evaluating harvest control rules with different biological reference points for the American lobster (Homarus americanus) fishery in the Gulf of Maine. – ICES Journal of Marine Science, 68: 1511–1524. The American lobster (Homarus americanus) supports one of the most valuable commercial fisheries in the United States. Controversy exists, however, in terms of the biological reference point (BRP) used in assessing lobster stock status, and there is no fully established or evaluated harvest control rule (HCR). A sex-specific, size-dependent operating model is developed to evaluate the performance of two HCRs, discrete and continuous, which adjust annual fishing mortality discretely and linearly, respectively, based on the status of the fishery. For each HCR, different BRPs are considered along with management duration, recruitment dynamics, and natural mortality. HCRs with a suitable set of BRPs can drive the fishery from an undesirable status to an optimal status. The continuous HCR tends to perform better than the discrete one. The Ftarget of 0.31 year−1 showed the best performance in the long term by balancing the needs of the fishing industry and conservation bodies. However, this was not the case in the short term. An Ntarget of 49.6 million would allow the American lobster to be maintained at its current stock level, with high recruitment and stable natural mortality. The study provides a framework for a systematic evaluation of management regulations for the American lobster.

Cannibals by night? In situ video monitoring reveals diel shifts in inter- and intra-specific predation on the American lobster

2013 ◽  
Vol 70 (11) ◽  
pp. 1635-1640 ◽  
Author(s):  
Noah G. Oppenheim ◽  
Richard A. Wahle
Keyword(s):  
Video Surveillance ◽  
Population Regulation ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Quantitative Information ◽  
Video Monitoring ◽  
Predatory Fish ◽  
American Lobster ◽  
Population Densities

We conducted tethering experiments in the field to evaluate day–night differences in the identity and frequency of predators encountered by the American lobster (Homarus americanus) in coastal Maine, USA. Separate daytime and nighttime deployments were conducted using tethered lobsters under infrared-illuminated video surveillance. Supplemental tethering trials without video surveillance provided further quantitative information on diel and size-specific predation patterns. We found crabs to be the most common predators during the day, whereas lobsters prevailed at night. Contrary to expectations, we measured higher predation rates at night than during the day, suggesting that nocturnal interactions with conspecifics may play a more important role in lobster population regulation than previously thought when lobster population densities are high and large predatory fish are rare. As large predatory groundfish have been depleted in the Gulf of Maine, lobster populations have reached historic highs, making density-dependent feedbacks such as cannibalism more likely.

scholarly journals Northeast Bathymetry and Backscatter Compilation: Western Gulf of Maine, Southern New England, and Long Island Sound

2021 ◽  
Author(s):  
Larry Ward ◽  
Paul Johnson ◽  
Michael Bogonko ◽  
Zachary McAvoy ◽  
Rachel Morrison
Keyword(s):  
New England ◽  
Gulf Of Maine ◽  
Long Island ◽  
Long Island Sound ◽  
Southern New England ◽  
Island Sound

scholarly journals Implications of ocean bottom temperatures on the catch ability of American lobster

2019 ◽  
Vol 79 ◽  
pp. 03007
Author(s):  
Xiaoxu Zhao ◽  
Pengwen Ding ◽  
Jilei Pang
Keyword(s):  
New England ◽  
Gulf Of Maine ◽  
Recent Decade ◽  
Temporal Variations ◽  
Effect Of Temperature ◽  
American Lobster ◽  
Ocean Bottom ◽  
Bottom Temperature ◽  
Using Data ◽  
The Impact

Since the beginning of the satellite era, the general trend of global and regional sea-surface temperature (SST) have continued to rise and, in the recent decade, the rate of warming has increased dramatically in the Gulf of Maine. However, due to variations in thermal stratification in the water column, SST is not the best measure to determine the impact on benthic organisms. So understanding the spatial and temporal variations of the ocean bottom temperature is critical to fisheries management. Since 2001, the Environmental Monitors on Lobster Traps (eMOLT) project has been implemented. The lobster fishermen have volunteered to collect bottom temperature and American lobster catch data from dozens of locations off the New England coast. Now we can use these data to analyze the relationship between ocean bottom temperature and lobster catch. Using data collected over the past decade, we examine the effect of temperature, temperature change, soak time and other factors on the catchability of lobsters. Our results suggest that there is a increase in catchability at the same time there is a) a temperature rise over many years and b) day-to-day temperature changes.

A simulation study to evaluate impacts of uncertainty on the assessment of American lobster fishery in the Gulf of Maine

2002 ◽  
Vol 59 (8) ◽  
pp. 1394-1403 ◽  
Author(s):  
Yong Chen ◽  
Carl Wilson
Keyword(s):  
Confidence Level ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
American Lobster ◽  
Large Uncertainty ◽  
Decision Confidence ◽  
The Status ◽  
Status Assessment ◽  
Lobster Fishery ◽  
Risk Managers

The status of the American lobster (Homarus americanus) in the Gulf of Maine (GOM) has been assessed for the last two decades by comparing an estimated current fishing mortality rate for females (Fcur) with a deterministically estimated biological reference point, F10%. The most recent assessment determined that GOM had exceeded the F10% for every year calculated, although in this time landings and abundance have doubled. The current policy does not consider uncertainty in the assessment. This study evaluates the impacts of uncertainty in F10% and Fcur on the status assessment of lobster fishery. Using a Monte Carlo simulation approach, we found that the status assessment would be influenced by uncertainties in estimating F10% and Fcur, and by the choice of decision confidence level reflecting the level of risk managers would like to take. A large uncertainty in Fcur and F10% and a high decision confidence level reduce the likelihood of defining the stock as overfished, and vice versa. Our results suggest that the probability of lobster overfishing may be less than previously thought, and that uncertainty in Fcur and F10% should be quantified and considered in determining the status of the GOM lobster stock.

Sign in / Sign up

Export Citation Format

Share Document