Evidence for thermally mediated settlement in lobster larvae (Homarus americanus)

2013 ◽  
Vol 70 (11) ◽  
pp. 1641-1649 ◽  
Author(s):  
Eric R. Annis ◽  
Carl J. Wilson ◽  
Robert Russell ◽  
Philip O. Yund
Keyword(s):  
Water Temperature ◽  
Settlement Patterns ◽  
Coastal Region ◽  
Homarus Americanus ◽  
Size Increase ◽  
Coastal Current ◽  
Bottom Temperature ◽  
Degree Days ◽  
Successful Recruitment ◽  
Behavioral Avoidance

We examined the potential for bottom temperatures ≤12 °C to inhibit successful recruitment of planktonic lobster postlarvae to the benthos. In laboratory trials, postlarvae held at 11 °C exhibited higher mortality, slower development, and reduced size increase at molt relative to postlarvae held at 13 °C. We sampled at field sites within Machias Bay, Maine (mean bottom temperature 12.39 °C, 46.1 degree-days ≥12 °C) and at the mouth of the bay (mean bottom temperature 11.57 °C, 5.1 degree-days ≥12 °C), where temperature was influenced by the cold Eastern Maine Coastal Current (EMCC). We found significantly higher settlement at the warm inshore site but, the abundance of competent planktonic postlarvae was not significantly different between sites, indicating a disconnect between postlarval abundance and settlement. Regional sampling of newly settled lobsters revealed a pattern of higher settlement at inshore sites extending across a broader coastal region impacted by the EMCC. Our results suggest that small differences in water temperature may shape settlement patterns through either behavioral avoidance of colder settlement sites or elevated postsettlement mortality of postlarvae settling at colder sites.

Diplosoma gumavirens (Ascidiacea, Didemnidae): the first record of photosymbiotic ascidians in the Taiwan Strait

2015 ◽  
Vol 8 ◽  
Author(s):  
Euichi Hirose ◽  
Mamiko Hirose ◽  
Jhy-Yun Shy
Keyword(s):  
Water Temperature ◽  
First Record ◽  
Taiwan Strait ◽  
Coastal Current ◽  
China Coastal Current ◽  
The Taiwan Strait ◽  
Penghu Islands

Diplosoma gumavirensspecimens were collected from the Penghu Islands, Taiwan. This is the first record of photosymbiotic ascidians in the Taiwan Strait, where the minimum water temperature in the winter is <16°C because of intrusion of the China Coastal Current.

Predicting walleye recruitment as a tool for prioritizing management actions

2015 ◽  
Vol 72 (5) ◽  
pp. 661-672 ◽  
Author(s):  
Gretchen J.A. Hansen ◽  
Stephen R. Carpenter ◽  
Jereme W. Gaeta ◽  
Joseph M. Hennessy ◽  
M. Jake Vander Zanden
Keyword(s):  
Data Availability ◽  
Degree Days ◽  
Shoreline Development ◽  
Thermal Habitat ◽  
Recruitment Success ◽  
Management Actions ◽  
Recruitment Failure ◽  
Successful Recruitment ◽  
Development Factor ◽  
Natural Reproduction

We classified walleye (Sander vitreus) recruitment with 81% accuracy (recruitment success and failure predicted correctly in 84% and 78% of lake-years, respectively) using a random forest model. Models were constructed using 2779 surveys collected from 541 Wisconsin lakes between 1989 and 2013 and predictor variables related to lake morphometry, thermal habitat, land use, and fishing pressure. We selected predictors to minimize collinearity while maximizing classification accuracy and data availability. The final model classified recruitment success based on lake surface area, water temperature degree-days, shoreline development factor, and conductivity. On average, recruitment was most likely in lakes larger than 225 ha. Low degree-days also increased the probability of successful recruitment, but primarily in lakes smaller than 150 ha. We forecasted the probability of walleye recruitment in 343 lakes considered for walleye stocking; lakes with high probability of natural reproduction but recent history of recruitment failure were prioritized for restoration stocking. Our results highlight the utility of models designed to predict recruitment for guiding management decisions, provided models are validated appropriately.

Evidence for water temperature increase in Lake George, NY: impact on growing season duration and degree days

2015 ◽  
Vol 31 (3) ◽  
pp. 241-253 ◽  
Author(s):  
Mark W. Swinton ◽  
Lawrence W. Eichler ◽  
Jeremy L. Farrell ◽  
Charles W. Boylen
Keyword(s):  
Water Temperature ◽  
Temperature Increase ◽  
Growing Season ◽  
Degree Days ◽  
Lake George

Determinants of Postmolt Size in the American Lobster (Homarus americanus). II. Folding of Premolt Cuticle

1994 ◽  
Vol 51 (8) ◽  
pp. 1774-1779 ◽  
Author(s):  
Jin-Hua Cheng ◽  
Ernest S. Chang
Keyword(s):  
Homarus Americanus ◽  
Size Increase ◽  
American Lobster ◽  
Eyestalk Ablation ◽  
Before And After ◽  
Rearing Condition

The effects of eyestalk ablation, regeneration, and rearing condition on the size of new cuticles before and after expansion were studied in juvenile Homarus americanus. Both eyestalk-ablated and intact lobster grew larger in large spaces than in small spaces. In contrast, regeneration reduced molt increment. Despite large differences in molt increment (percentage of size increase during a molt) among experimental groups, the percentage of postmolt size increase that could be accounted for by unfolding of the new cuticle was large and constant in each group. In addition, transferring freshly molted lobster to dilute seawater did not produce any further size increase but instead caused cuticle breakage in some animals. We conclude that molt increment in lobster is determined by regulating the size of the cuticle before ecdysis. The size of the postmolt cuticle is primarily a result of unfolding of the new, previously folded cuticle.

scholarly journals Descriptive Capability of Datasets as Proxy of Sea Water Temperature in Coastal Systems: An Evaluation from the Aegean Sea

2021 ◽  
Vol 21 (12) ◽  
pp. 627-635
Author(s):  
Fethi Bengil ◽  
Sinan Mavruk ◽  
Zafer Kızılkaya ◽  
Elizabeth G. T. Bengil ◽  
Vahit Alan ◽  
...  
Keyword(s):  
Water Temperature ◽  
Sea Water ◽  
Seawater Temperature ◽  
Coastal Region ◽  
Aegean Sea ◽  
Careful Consideration ◽  
In Situ Conditions ◽  
Diverse Data ◽  
Time Frames

Scientific and technological progresses have introduced diverse data sources for seawater temperature over broad temporal and spatial ranges. Here, we investigated the performance of satellite and model-based seawater temperature data for different temporal composites and depths. We applied an in-situ temperature time-series obtained in a coastal bottom in the Aegean Sea over three years, as the reference. Both datasets showed largely significant relationships based on cross-correlation analyses and presented descriptive properties of the in-situ conditions at corresponding depths. Based on the results of analyses, the modeling datasets presented more reliable results and representations of in-situ conditions than the datasets obtained from satellite for the coastal region. However, the datasets obtained from the satellite also provided reliable data for all time frames investigated, particularly in the mixed surface layer. Monthly datasets were more effective in providing descriptive values in long term studies. This is the first detailed study to explore the descriptive capacities of modeling for water temperature in coastal environments. According to the results, the selection of a dataset as a proxy for seawater temperature requires careful consideration. The present study provides an extensive baseline for evaluating the suitability of the application of specific datasets as proxies in coastal ecosystems.

A comparison of the size at maturity of female American lobsters (Homarus americanus) over three decades and across coastal areas of the Gulf of Maine using ovarian staging

2021 ◽  
Author(s):  
Jesica D Waller ◽  
Kathleen M Reardon ◽  
Sarah E Caron ◽  
Blaise P Jenner ◽  
Erin L Summers ◽  
...  
Keyword(s):  
Egg Production ◽  
Gulf Of Maine ◽  
Stock Assessment ◽  
Coastal Region ◽  
Homarus Americanus ◽  
Growth Patterns ◽  
American Lobster ◽  
Size At Maturity ◽  
Management Measures ◽  
Production Growth

Abstract The carapace length (CL) at which American lobster (Homarus americanus) females reach maturity can be used to evaluate egg production, growth patterns, and the overall health of lobster stocks. The female maturity datasets used to represent Gulf of Maine (GOM) lobsters in the 2015 Atlantic States Marine Fisheries Commission American Lobster Stock Assessment were collected in the 1990s by the Maine Department of Marine Resources at two coastal sites. Many studies have demonstrated an inverse relationship between temperature and the size at maturity in female lobsters, and GOM waters have warmed significantly over this period. To update these GOM maturity datasets, we used ovarian staging to determine the maturity status of over 1200 females from fives sites over 3 years. Broad application of this methodology in tandem with key growth measurements on females 50–120 mm CL allowed us to characterize reproductive development and generate maturity ogives (proportion mature at a given CL). We observed a latitudinal gradient in the size at maturity across this coastal region of the GOM and quantified a decrease in this size over 25 years. These findings have implications for future stock assessment approaches and management measures implemented to sustain this valuable fishery.

scholarly journals Temperature structure and characteristics appearing on SSM/I images of the Cosmonaut Sea, Antarctica

1994 ◽  
Vol 20 ◽  
pp. 298-306 ◽  
Author(s):  
Takatoshi Takizawa ◽  
Kay I. Ohshima ◽  
Ushio Shcki ◽  
Toshiyuki Kawamura ◽  
Hiroyuki Enomoto
Keyword(s):  
Water Temperature ◽  
Deep Water ◽  
Cold Water ◽  
Coastal Region ◽  
Water Area ◽  
Temperature Structure ◽  
Circumpolar Deep Water ◽  
Convergence Line ◽  
Coastal Polynya ◽  
Cosmonaut Sea

Water-temperature structure in the Cosmonaut Sea at 60 68° S, 35 65° E in 1987–92 shows that cold water with a temperature below -1.5°C was present in the coastal region. The Circumpolar Deep Water with a temperature higher than 1.0°C was found below about 150m depth from northeast to northwest of the cold water area. The SSM/I images in 1987–91 indicate that polynya activities were intensive in 1988 and the typical Cosmonaut Polynya was observed; due to weaker activities, the small and sporadic Cosmonaut Polynya formed in 1987, 1989, 1990 and 1991. A coastal polynya was frequently observed every year at about 66° S, 50–60° E. A train of polynyas to the east of Cosmonaut Polynya often appeared. It is considered that the Atmospheric Convergence Line and Antarctic Divergence Region are responsible for polynya activities in the Cosmonaut Sea.

Migratory Movements of Ovigerous Lobsters, Homarus americanus, Tagged off Grand Manan, Eastern Canada

1986 ◽  
Vol 43 (11) ◽  
pp. 2197-2205 ◽  
Author(s):  
Alan Campbell
Keyword(s):  
Homarus Americanus ◽  
Shallow Waters ◽  
Bay Of Fundy ◽  
Degree Days ◽  
Eastern Canada ◽  
Egg Development ◽  
Sufficient Degree ◽  
Positive Correlations ◽  
Hatching Eggs ◽  
Migratory Movements

A total of 2139 ovigerous lobsters, Homarus americanus, were tagged and egg development recorded off Grand Manan, eastern Canada, during 1982–83. Recaptures during August 1982 to January 1984 totaled 1877, representing 1046 individuals including 457 that were captured 2–10 times. The single recapture data indicate that the majority (75%) of the lobsters moved < 15 km. Use of distance moved information from single recaptures of lobsters at liberty for long periods can be misleading, since exact distance moved between tag release–recapture points usually is unknown. Multiple recapture and depth at recapture data gave more information on the movements of the lobsters. Many lobsters showed seasonal shallow-deep migrations of > 20 km with recaptures in shallow (< 20 m) water during summer–fall and in deep (> 200 m) water during winter–spring. Many ovigerous females returned to the Grand Manan area the following summer. A few (7%) moved north > 30 km into the Bay of Fundy and south as much as 322 km along the coastline of Maine. Examination of the multiple recapture data between months indicated positive correlations between change in depth, distance moved, and water temperature. The seasonal depth migrations of ovigerous lobsters appear to be associated with maximizing temperatures which provide sufficient degree-days for completion of egg development. Also, hatching eggs in relatively warm shallow waters may confer a survival advantage for pelagic lobster larvae by decreasing development time to the benthic stage.

Impacted Stress: A Causal Agent of Reduced Whitefish (Coregonus Iavaretus) Egg Incubation Time

1988 ◽  
Vol 45 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Tor F. Næsje ◽  
Bror Jonsson
Keyword(s):  
Water Temperature ◽  
Incubation Period ◽  
Incubation Time ◽  
Natural Water ◽  
Flowing Water ◽  
Degree Days ◽  
River Temperature ◽  
Egg Incubation ◽  
Heated Water ◽  
Two Samples

The purpose of these experiments was to investigate whether whitefish (Coregonus Iavaretus) eggs subjected to induced agitation had a shorter incubation period to hatching than undisturbed incubating eggs. Eyed eggs were divided into four main groups: two incubated at river temperatures and two incubated in heated water. River temperature was 2 °C at the beginning of the experiment and increased to more than 10 °C at hatching. Heated water temperatures varied between 6.5 and 8.5 °C. One sample with four replicates at each incubating water temperature was continuously agitated with flowing water, while two samples with four replicates each were incubated undisturbed. At both temperatures, eggs kept in motion by flowing water hatched at fewer degree-days (heated water: 380 ± 6.4, natural water: 417 ± 6.6) from fertilization to 50% hatching than those laying undisturbed (heated water: 513 ± 10.5, natural water: 470 ± 7.3). Eggs agitated during incubation hatched with greater synchrony than those incubated undisturbed. Larvae incubated at river temperatures were larger than those incubated in heated water. Our findings revealed that eggs can hatch at different incubation stages during the ontogeny when exposed to varying environmental stimuli.

Effects of Water Temperature and Housing Conditions upon the Aggressive Behavior of the Lobster Homarus americanus

1975 ◽  
Vol 32 (5) ◽  
pp. 713-717 ◽  
Author(s):  
Ronald S. Hoffman ◽  
Philip J. Dunham ◽  
Patrick V. Kelly
Keyword(s):  
Aggressive Behavior ◽  
Water Temperature ◽  
Homarus Americanus ◽  
Housing Conditions ◽  
Test Situation ◽  
Visual Contact ◽  
Physical Isolation

Lobsters are more aggressive at 10 C than at 5 C. At 10 C, animals housed communally, and those in physical isolation with visual contact, are less aggressive in a test situation than lobsters housed with no physical or visual contact.

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