Distance Chemoreception and Vision in the Selection of Prey by American Lobster (Homarus americanus)

1978 ◽  
Vol 35 (7) ◽  
pp. 1006-1008 ◽  
Author(s):  
R. W. M. Hirtle ◽  
K. H. Mann
Keyword(s):  
Response Time ◽  
Key Words ◽  
Mytilus Edulis ◽  
Sea Urchins ◽  
Carcinus Maenas ◽  
Homarus Americanus ◽  
Strongylocentrotus Droebachiensis ◽  
American Lobster ◽  
Selection Of

Lobsters responded positively to the waterborne odor of intact living crabs (Carcinus maenas), sea urchins (Strongylocentrotus droebachiensis), and mussels (Mytilus edulis). The frequency of response was higher and the response time shorter to crabs than to sea urchins or mussels. Lobsters also responded to the sight of moving crabs or moving sea urchins, but not to the sight of stationary specimens. Crabs are probably more attractive to lobsters because of their odor and their greater activity, compared with sea urchins or mussels. Key words: lobsters, prey, chemoreception, vision, crabs, sea urchins, movement, odor

scholarly journals LARGE EPIBENTHIC INVERTEBRATES IN THE BRAS D’OR LAKES

2002 ◽  
Vol 42 (1) ◽  
Author(s):  
M. John Tremblay
Keyword(s):  
Egg Production ◽  
Carcinus Maenas ◽  
Homarus Americanus ◽  
Strongylocentrotus Droebachiensis ◽  
Green Crab ◽  
American Lobster ◽  
Placopecten Magellanicus ◽  
Cancer Irroratus ◽  
Trawl Surveys ◽  
Epibenthic Invertebrates

The distribution of large epibenthic invertebrates (lobster and crabs, bivalve molluscs and echinoderms) in the Bras d’Or Lakes is reviewed, and possible limiting factors are identified. The review is based on published and unpublished studies, including recent trawl surveys directed at fish, and trapping studies directed at American lobster Homarus americanus and green crab Carcinus maenas. The reduced salinities within the Lakes probably limit the distribution of several species (rock crab Cancer irroratus, sea scallop Placopecten magellanicus and possibly American lobster), particularly during the more sensitive larval period. Lobsters and eastern oysters Crassostrea virginica serve to illustrate the multiple factors limiting epibenthic invertebrate distribution within the Bras d’Or Lakes. Lobsters are less abundant within the Bras d’Or Lakes than on the outer coast of Cape Breton Island. Possible reasons are the reduced salinity and limited cobble bottom substrate in the Bras d’Or Lakes, coupled with low food availability and low egg production. Low egg production may be the result of overfishing of lobsters in the past. The life history and physiology of the eastern oyster appears to be well suited to the areas of the Lakes with warm summer temperatures. The oyster populations in the Bras d’Or Lakes are limited by natural predators (e.g. starfish and green crab), competitors (e.g. blue mussel Mytilus edulis and M. trossulus), and overfishing. The green crab, a new arrival to the Bras d’Or Lakes, will likely have negative effects on bivalves such as oysters, but the overall effect of green crab on the Bras d’Or Lakes food web is difficult to predict. Recent trawl surveys indicate both sea urchins Strongylocentrotus droebachiensis and starfish are present in considerable abundance, but little is known about their ecological roles in the Bras d’Or Lakes.La distribution des grands invertébrés épibenthique (les homards et les crabes, les mollusques bivalves et les échinodermes) dans les lacs du Bras d’Or est examinée et les coefficients possiblement limitatifs sont identifies. La revue est basée sur des études publiées et non-publiées englobant les plus récentesétudes sur la pêche au chalut dirigées vers les poissons et les études sur la pêche aux casiers dirigées vers les homards américains Homarus americanus et les crabes verts Carcinus maenas. Salinités réduites dans les lacs du Bras d’Or limitent probablement la distribution de quelques espèces crabes roches Cancer irroratus, pétoncle géant Placopecten magellanicus et possiblement le homard américain, en particulier, pendent l’époque sensible du larvaire. Les homards et les huîtres de l’Est Crossostrea virginica montrent plusieurs facteurs coefficients limitatifs de la distribution des invertébrés épibenthique dan les lacs du Bras d’Or. Les homards sont moins abondants ici que sur la côte extérieure de L’Ille du Cap Breton. Des explications possibles sont la réduction de l’eau saline du pavé rond limite dans le substratum de lacs, ainsi que la pauvre disponibilité de mangé et la production basse des oeufs. Cette dernière est peut-être le résultat d’un trop grand prise de homards au passè. L’histoire et la physiologie des huîtres semblent être bien adaptés aux lieux des lacs de Bras d’Or, qui ont des temperatures chaudes dan l’été. La population des huîtres dans les lacs est limitée par des proies natures ( ie étoiles de mer et les crabes verts) compétiteurs ( ie. Moules bleus Mytilus edulis et M. trossulus) et une trop grande prise de poissons. Le crabe vert, une arrivée nouvelle dans les lacs du Bras d’Or va sans doute avoir des impacts négatifs sur les bivalues comme les huîtres, mais leurs impacts en general sur la chaîne nutritive est difficile à prédire. Les études les plus recents sur la pêche au chalut montrent qu’il y a ungrand nombre d’oursins de mer Strongylocentrotus droebachiensis et des étoiles de mer, mais on ne connait pas quel est leur rôle écologique dans les lacs du Bras d’Or.

Relationship Between Destructive Grazing by the Sea Urchin, Strongylocentrotus droebachiensis, and the Abundance of American Lobster, Homarus americanus, on the Atlantic Coast of Nova Scotia

1981 ◽  
Vol 38 (11) ◽  
pp. 1339-1349 ◽  
Author(s):  
W. G. Wharton ◽  
K. H. Mann
Keyword(s):  
Population Structure ◽  
Nova Scotia ◽  
Sea Urchins ◽  
Atlantic Coast ◽  
Homarus Americanus ◽  
Strongylocentrotus Droebachiensis ◽  
American Lobster ◽  
History Of ◽  
Kelp Bed ◽  
The Relationship

Relationships between percentage cover of macroalgae, population structure of sea urchins (Strongylocentrotus droebachiensis), and the history of the lobster fishery were examined at nine sites distributed along the Atlantic coast of Nova Scotia from Guysborough County in the northeast to Pubnico in the southwest. At Pubnico there was dense algal cover and a small number of urchins living in crevices, and at Cape Sable there was an area of transition, but at all other sites there were urchin-dominated barren grounds. When the population structure of the urchins was compared with that previously observed in St. Margaret's Bay before, during, and after destruction of beds of kelp (Laminaria spp. and Agarum) by overgrazing, it was concluded that kelp bed destruction occurred on the coast north of Halifax prior to 1970, and on the coast south of Halifax after 1970. From the records of American lobster (Homarus americanus) catches it was concluded that a critical decline in catches at each site occurred a few years after kelp bed destruction. Information from various sources is synthesized into a coherent theory of the relationship between lobsters, other predators, sea urchins, and kelp.Key words: lobsters, Homarus americanus; sea urchins, Strongylocentrotus droebachiensis; destructive grazing, kelp, Laminaria, Agarum

Selection of Prey by American Lobsters (Homarus americanus) When Offered a Choice Between Sea Urchins and Crabs

1977 ◽  
Vol 34 (11) ◽  
pp. 2199-2203 ◽  
Author(s):  
Patricia D. Evans ◽  
Kenneth H. Mann
Keyword(s):  
Key Words ◽  
Sea Urchin ◽  
Direct Observation ◽  
Food Preference ◽  
Sea Urchins ◽  
Homarus Americanus ◽  
Cancer Irroratus ◽  
Feeding Experiments ◽  
Selection Of

American lobsters (Homarus americanus) were presented with various numerical combinations of sea urchins (Strongyhcentrotus droebachiensis) and rock crabs (Cancer irroratus) in long-term laboratory feeding experiments. They exhibited a 5:1 preference for crabs when the numerical ratio of urchins to crabs varied from 0.25:1 to 8:1. Lobsters presented with a superabundance of sea urchins (urchin:crab ratios of 16:1 and 100:1) maintained relatively constant proportions of urchins and crabs in their diet. Direct observation indicated that lobsters feed selectively. Their role as key predators in kelp–sea urchin communities is discussed. Key words: food preference, predation, Canadian Atlantic, bioenergetics

The Hemolymph Bactericidin of American Lobster (Homarus americanus): Adsorption and Activation

1978 ◽  
Vol 35 (11) ◽  
pp. 1504-1507 ◽  
Author(s):  
Katsuyoshi Mori ◽  
James E. Stewart
Keyword(s):  
Key Words ◽  
Homarus Americanus ◽  
American Lobster ◽  
Aerococcus Viridans

The bactericidin of American lobster (Homarus americanus) hemolymph was adsorbed readily by representatives of two bacterial genera: a nonpathogen, Pseudomonas perolens, and the lobster pathogen Aerococcus viridans (var.) homari. Activation of the bactericidin by factor(s) secreted by the hemocytes can occur before adsorption and also after adsorption by bacteria. Although the lobster pathogen A. viridans (var.) homari is unaffected by the activated bactericidin, this lack of effect is not related to adsorption since this bacterium adsorbs the bactericidin as readily and completely as does the susceptible nonpathogen. Key words: lobster, Homarus americanus, plasma bactericidin, adsorption and activation, hemocytic activator, Pseudomonas perolens, Aerococcus viridans (var.) homari

scholarly journals A field-based investigation of behavioural interactions between invasive green crab (Carcinus maenas), rock crab (Cancer irroratus), and American lobster (Homarus americanus) in southern Newfoundland

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8444
Author(s):  
Nicola Zargarpour ◽  
Cynthia H. McKenzie ◽  
Brett Favaro
Keyword(s):  
Carcinus Maenas ◽  
Positive Association ◽  
Homarus Americanus ◽  
Green Crab ◽  
American Lobster ◽  
Catch Per Unit Effort ◽  
Cancer Irroratus ◽  
Species Invasions ◽  
Rock Crab ◽  
Catch Rates

Marine species invasions pose a global threat to native biodiversity and commercial fisheries. The European green crab (Carcinus maenas) is one of the most successful marine invaders worldwide and has, in the last decade, invaded the southern and western coastal waters of the island of Newfoundland, Newfoundland and Labrador (NL), Canada. Impacts of green crab on the American lobster (Homarus americanus), which are native to Newfoundland, are not well understood, particularly for interactions around deployed fishing gear. Declines in lobster catch rates in invaded systems (i.e., Placentia Bay, NL), have prompted concerns among lobster fishers that green crab are interfering with lobster catch. Here, we conducted a field experiment in a recently-invaded bay (2013) in which we deployed lobster traps pre-stocked with green crab, native rock crab (Cancer irroratus) (a procedural control), or empty (control). We compared catch per unit effort across each category, and used underwater cameras to directly observe trap performance in situ. In addition, we used SCUBA surveys to determine the correlation between ambient density of lobster and green crab in the ecosystem and the catch processes of lobster in traps. We found: (1) Regardless of the species of crab stocked, crab presence reduced the total number of lobster that attempted to enter the trap, and also reduced entry success rate, (2) lobster consumed green crab, rock crab and other lobster inside traps and (3) there was a positive association between lobster catch and ambient lobster density. Our results suggest that while there was a relationship between in-trap crab density and trap catch rates, it was not linked to the non-native/native status of the crab species.

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