lobster

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lobster
European lobster (Homarus gammarus), specimen with right scissors as K scissors

European lobster ( Homarus gammarus ), specimen with right scissors as K scissors

Systematics
Class : Higher crabs (Malacostraca)
Order : Decapods (decapoda)
Subordination : Pleocyemata
Partial order : Large crayfish (Astacidea)
Family : Lobster-like (Nephropidae)
Genre : lobster
Scientific name
Homarus
Weber , 1795

The lobsters ( Homarus ) are a marine genus of the decapods (Decapoda) from the family of the lobster-like (Nephropidae). Today it includes the two types of American lobster and European lobster .

distribution

European lobster ( Homarus gammarus ), clearly recognizable here with Z-scissors on the left
American lobster ( Homarus americanus ), here left scissors designed as Z scissors

The American lobster is native to the waters off the North American east coast from the Canadian province of Labrador in the north to the US state of North Carolina in the south. This species has been known as a neozoon since 1999 on the North Sea coast of Sweden, Denmark and Norway. It is believed that these animals were naturalized there by humans.

The European lobster is found on the shelf of the European Atlantic coast, in the North Sea, in the Mediterranean and in the western Black Sea. It stretches from the Lofoten in the north to Morocco in the south, the Azores in the west and Israel in the east; it is not native to the Baltic Sea.

description

features

Adult lobsters are usually between 30 and 64 centimeters long and weigh about 1 to 6 kilograms. A lobster's growth does not peak, but it slows down as it ages. The largest European lobster ever caught was 1.26 meters long and 9.3 kilograms, with the cracking claw alone weighing 1.2 kilograms. With a record weight of 20.1 kilograms, an American lobster was even more than twice as heavy.

The color of lobsters varies widely from a strong blue to dark purple tones and depends on the food and the color of the rock in their habitat. Yellow coloring and albinism are very rare. The flanks of the animals are usually yellowish to brown with darker, often reddish speckles.

The end links on the first pair of legs (pereiopods I) of the lobster are clearly differently designed claws ( chelae ) on the right and left : You can use stronger snapping scissors (also known as knot or K scissors) compared to slender gripping scissors with fine teeth on the inside (also cutting scissors). or called Z-scissors). With a larger sample, the cracking scissors can be both the right and left scissors in a ratio of almost 50:50. The palm of the scissors is always less than twice as long as the scissor finger (Dactylus). The second and third pair of legs also have scissors, which are much smaller and symmetrical. The pereiopods IV and V do not end in claws. The scissors are always smooth and hairless.

Adult males are usually larger than adult females. The male's claws are larger in proportion to the length of their bodies, while the female's abdomen is wider. In addition, the first pair of swimming legs ( pleopods ) in males are hardened, while in female lobsters these are soft and pliable.

The two species of lobster have a very smooth exoskeleton compared to other species of lobster-like . On the carapace there are rather inconspicuous depressions or ridges, the individual somites of the abdomen are uniformly smooth and even. With the exception of a few tips, the scissors are always smooth and hairless.

ecology

Lobsters live in the sublittoral areas of the sea coasts at depths of up to 480 meters, but are mostly found at depths of 4 to 50 meters, where they prefer solid seabed or rocks as bentonts . The settled temperature range of the habitat ranges from 5 to 20 ° C, whereby extreme temperatures of 1 ° C and 35 ° C can be tolerated for a short time.

Lobsters live individually in burrows or crevices that they leave to eat at night. The diet consists of invertebrates such as small crustaceans, mollusks , sea urchins, starfish and poly bristles . Cannibalism can occur in aquariums with dense populations, but is rare in nature.

Adult animals are locally loyal; European lobsters migrate on a smaller scale, while American lobsters can migrate larger.

On the coast of Heligoland , where the rocky underwater reliefs provide ideal living conditions for lobsters, the formerly large crustacean populations would not be able to survive in the long term without regular reintroduction of young animals due to the pollution and warming of the ocean. The remaining five licensed fishermen on the island work together with the participating biologists by delivering captured egg-bearing female lobsters free of charge. In order to create a new habitat for the lobster, the stone embankments under the wind turbines in the German Bight were provided with young lobsters from 2014. The odds were seen as promising.

Reproduction and life cycle

European lobster larva
Fusion image lobster
Fusion image lobster
Juvenile European lobster

Males woo females by creating a mating den, usually in autumn. This serves primarily to protect the female, because she has to shed her armor for sexual union because it blocks the sex organ. Without the exoskeleton , the female is now completely defenseless and dependent on the male's help. The female now begins to put on a new tank. After about seven days, the still thin lime shell wears so far that the actual mating can take place. The copulation is done belly to belly and only takes five seconds. The male hands over a packet of sperm that the female uses to fertilize the eggs at a later time. For a further week, the male protects his partner until the armor is completely hardened again.

Females keep the packets of seeds, the external fertilization of the eggs usually takes place in the following summer. The female attaches up to 60,000 eggs to the underside of her abdomen on the swimming legs (pleopods). They can stay there for up to 11 months, so females can be found with eggs almost all year round. Fresh eggs have a dark green color, are then black and reddish when the embryos are almost completely developed. The eggs of the lobsters are relatively large compared to other crustaceans and the number of eggs is rather small in comparison.

The larvae live planktonically and are omnivores. Depending on the water temperature, they shed their skin three times within 22 to 100 days and are then around 12 millimeters in size. Only about 0.005% of the larvae of the European lobster survive this stage of life. The lobster larvae then look for a sheltered spot on the seabed or dig into the seabed and stay there for two to three years. Now as Benthont , lobsters usually become sexually mature at an age of four years.

In the first year of life, lobsters molt up to ten times, with increasing age the molting rate drops suddenly over several years. The length of the carapace increases by 10% to 20% per molt .

Lobsters grow by molting their hard exoskeleton, which they shed frequently: the average lobster can molt up to 44 times before it's a year old. When lobsters reach the age of seven, they molt once a year and then every two to three years thereafter. Each molting process requires more energy than previous ones because the lobster grows in size.

Systematics

The genus today includes the two species Homarus americanus H. Milne-Edwards 1837 and Homarus gammarus L. 1758; eight other fossil species are known.

A distinguishing feature of the two recent species is the lack of sting on the underside of the rostrum on the carapace of the European lobster. However, a reliable differentiation between American and European lobsters is only possible through genetic testing.

From artificial insemination it is known that American and European lobsters can sire hybrids. That this can also occur in nature has so far been highly unlikely, as the distribution areas do not overlap and the partner selection takes place mainly within the species. Nevertheless, a female American lobster carrying hybrid eggs was caught off Norway in autumn 2009. Whether these hybrids are sterile or fertile is the subject of research.

The cape mummer ( Homarinus capensis ), which used to belong to this genus , has been placed in the monotypical genus Homarinus due to the hairiness of the claws and its much smaller body size .

Lobsters and people

Conservation

Lobster trap
The lobster is considered a difficult dish .

In order to protect the population, landed lobsters may not be less than certain minimum lengths that differ from region to region. For example in Massachusetts , where a carapace of at least 3 1/4 inches (approx. 8 cm) is required. In Schleswig-Holstein the minimum length including the rostrum is 11 cm.

The 2009 catch was 100,000 t of American lobster and around 4,500 t of European lobster. Despite this fishing, the populations of both species are considered stable or increasing.

Catch and processing

Lobsters as a food are a well-known delicacy and are therefore fished in a regulated manner. As a rule, this is done with traps, the so-called lobster baskets , into which the animals can get in, but due to the design they cannot leave again.

After the catch, the claws are tied together to prevent cannibalism . They are then taken to their destination in small styrofoam containers.

The killing of lobsters is regulated in Germany by the ordinance for the protection of animals in connection with slaughter or killing (TierSchlV): According to this, crustaceans must be put in strongly boiling water, which completely covers the body and continues to boil after its addition, or electrically or be killed after electrical stunning. In Germany, live crustaceans may only be transported in water or temporarily on a damp surface. From animal rights activists this practice and the nature and duration criticized transport.

According to a publication by the European Food Safety Authority (EFSA) , cooking live lobsters is likely to cause pain and suffering in them, as does piercing the animals.

Another method of killing a lobster is by slicing the live animal. First, the head section is divided lengthways with a targeted cut and the lobster is then cut up. This method, which is banned in Germany, is mainly used in classic French cuisine, but also in Asia. The raw lobster meat obtained in this way can now also be prepared using other cooking methods than cooking.

In Switzerland , a Federal Council decision in 2018 extended the stunning obligation, which previously only applied to vertebrate animals, to include crayfish . Since then, it has been forbidden to immerse non-anesthetized lobsters in boiling water, which is common in gastronomy . In addition, they are no longer allowed to be transported directly on ice or in ice water and species living in water must always be kept in their natural environment . An import ban was rejected by the National Council.

Types of preparation

Of the many possible types of preparation, two should be mentioned that can be confused with French-language menus. Both species are killed as described above by immersion in bubbling boiling water.

  • Homard à l'armoricaine (Breton style lobster)

After cooking, the lobster is cut up, seared, flambéed, steamed with tomato pieces and spices and served ready to eat.

  • Homard à l'américaine (American style lobster)

After cutting lengthways, the lobster is not released and cooked with a little tomato paste and spices. The alcoholic beverages are used to extinguish.

Negligible senescence

Lobsters get more fertile and stronger the older they get, not the other way around. The key to this is believed to be telomerase , which is able to rejuvenate their cells indefinitely: lobsters produce enough of this substance to renew their telomeres and prevent cells from dying. This mechanism is so effective that those animals that are 60 or 70 years old are just as fertile as those a few decades younger.

swell

literature

  • Lipke B. Holthuis : Marine Lobsters of the World . An Annotated and Illustrated Catalog of Species of Interest to Fisheries Known to Date. Ed .: Food and Agriculture Organization (=  FAO Fisheries Synopsis . Volume 125 ). Rome 1991, ISBN 978-92-5103027-1 .

Individual evidence

  1. ↑ a b c d Species Fact Sheets Homarus gammarus. Food and Agriculture Organization of the United Nations, accessed November 19, 2011 .
  2. ^ A b c Gro I. van der Meeren, Josianne Støttrup, Mats Ulmestrand, Jan Atle Knutsen: Invasive Alien Species Fact Sheet: Homarus americanus . Ed .: Online Database of the North European and Baltic Network on Invasive Alien Species. NOBANIS. 2006 ( nobanis.org [PDF; 138 kB ]).
  3. ↑ a b c d Species Fact Sheets Homarus americanus. Food and Agriculture Organization of the United Nations, accessed November 19, 2011 .
  4. ↑ a b c Homarus gammarus in the endangered Red List species the IUCN 2011. Posted by: M. Butler, A. Cockcroft, A. MacDiarmid, R. Wahle, 2011. Accessed November 19, 2011th
  5. ↑ see Holthuis, p. 58.
  6. ↑ a b c d Biology of the European Lobster, Homarus gammarus. The National Lobster Hatchery, accessed November 5, 2015 .
  7. ↑ Heaviest Marine Crustacean. Guinness World Records, archived from the original on May 28, 2006 ; accessed on November 19, 2011 (English).
  8. ↑ Albino Lobster Pulled From Sea. (No longer available online.) Thebostonchannel.com, July 28, 2010, archived from the original on December 22, 2011 ; accessed on November 20, 2011 (English). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.thebostonchannel.com
  9. ↑ see Holthuis, p. 17.
  10. ↑ a b c d J. Stanley Cobb, Kathleen M. Castro: Homarus Species . In: Bruce Phillips (Ed.): Lobsters: Biology, Management, Aquaculture and Fisheries . Wiley-Blackwell, Oxford, UK; Ames, Iowa 2006, ISBN 1-4051-2657-4 .
  11. ↑ a b c Eleanor Ely: The American Lobster. In: Rhode Island Sea Grant. University of Rhode Island, June 3, 1998, archived from the original June 23, 2012 ; accessed on November 29, 2015 .
  12. ^ Lipke B. Holthuis: The Lobsters of the Superfamily Nephropidea of ​​the Atlantic Ocean (Crustacea: Decapoda) . In: Bulletin of Marine Science . tape 24 , no. 4 , 1974, p. 723–884 ( nhm.org [PDF; 16.0 MB ; accessed on July 4, 2012]).
  13. ↑ a b Homarus americanus in the endangered Red List species the IUCN 2011. Posted by: M. Butler, A. Cockcroft, A. MacDiarmid, R. Wahle, 2011. Accessed November 19, 2011th
  14. ↑ Fed up of lobster? The Helgoland Experiment ( Memento of the original from October 6, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , 30-minute NDR documentary about the New Hummer Habitat project, accessed October 5, 2017 @1@ 2Template: Webachiv / IABot / www.ardmediathek.de
  15. ↑ Michael Miersch: Lobsters drop all casings. welt.de, March 22, 2010, accessed on August 22, 2017 .
  16. ↑ T. Wolff: Maximum size of lobsters ( Homarus ) (Decapoda, Nephropidae) . In: Crustaceana . Vol. 34, 1978, pp. 1-14 , doi : 10.2307 / 20103244 .
  17. ↑ Sammy De Grave, N. Dean Pentcheff, Shane T. Ahyong et al .: A classification of living and fossil genera of decapod crustaceans . In: Raffles Bulletin of Zoology Suppl. Volume 21 , 2009, p. 1–109 ( edu.sg [PDF; 7,8 MB ; accessed on November 20, 2011]).
  18. ↑ Knut E. Jørstad, PA Prodohl, A.-L. Agnalt, M. Hughes, E. Farestveit, AF Ferguson: Comparison of genetic and morphological methods to detect the presence of American lobsters, Homarus americanus H. Milne Edwards, 1837 (Astacidea: Nephropidae) in Norwegian waters . In: Hydrobiologia . tape 590 , 2007, pp. 103-114 , doi : 10.1007 / s10750-007-0762-y .
  19. ^ Marie Hauge: Unique lobster hybrid. Institute of Marine Research Norway, May 2010, accessed November 21, 2011 .
  20. ↑ Irv Kornfield, Austin Williams, Robert S. Steneck: Assignment of Homarus capensis (Herbst, 1792), the Cape lobster of South Africa, to Homarius new genus (Decapoda: Nephropidae) . In: Fishery Bulletin . tape 93 , no. 1 , 1995, ISSN  0090-0656 , p. 97-102 ( noaa.gov [PDF; 810 kB ; accessed on November 19, 2011]).
  21. ↑ Commercial regulations summary tables for finfish, shellfish & seaworms, and lobster & crabs. Massachusetts Department of Fish and Game, accessed November 29, 2015 .
  22. ↑ Schleswig-Holstein Coastal Fishing Regulations. (PDF) February 17, 2005, accessed on November 20, 2011 (PDF file, 110 kB).
  23. ↑ Thomas Fröhlich: Animal welfare-friendly keeping of lobsters and lobsters . In: Federal Association of Civil Servants Veterinarians e. V. (Ed.): Official veterinary service and food control . tape 4 , 1997, p. 254 .
  24. ↑ Section 12, Paragraph 11 of the Animal Welfare Slaughter Ordinance (TierSchlV)
  25. ↑ Section 13 (2) of the Animal Welfare Transport Ordinance (TierSchTrV) as a special national regulation compared to Regulation (EC) No. 1/2005 that is otherwise applicable in the EU
  26. ↑ EFSA Journal: Aspects of the biology and welfare of animals used for experimental and other scientific purposes . No. 292 , 2005, pp. 105 (American English, europa.eu [PDF; 1.4 MB ; accessed on January 17, 2014]).
  27. ^ The Culinary Institute of America (Ed.): The Professional Chef . 9th edition. John Wiley & Sons , Hoboken, New Jersey 2011, ISBN 978-0-470-42135-2 , pp. 413 f .
  28. ↑ Changes to ordinances in the veterinary sector In: admin.ch, January 10, 2018, accessed on January 10, 2018.
  29. ↑ Lobsters can only be cooked in a stunned state.In : srf.ch, January 10, 2018, accessed on January 10, 2018.
  30. ↑ 140-year-old lobster's tale has a happy ending. Associated Press, January 10, 2009, accessed January 1, 2010 .

Remarks

  1. ↑ For example from peta ( Memento of the original dated February 12, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , the Albert Schweitzer Foundation for our environment and the German Animal Welfare Association . @1@ 2Template: Webachiv / IABot / www.peta.de

Web links

Wiktionary: Hummer  - explanations of meanings, word origins, synonyms, translations
Commons : Hummer  album with pictures, videos and audio files