{"id":58301,"date":"2016-04-18T00:00:00","date_gmt":"2016-04-18T00:00:00","guid":{"rendered":"https:\/\/www.uri.edu\/news-draft\/uncategorized\/uri-researcher-invasive-crabs-changing-ecology-of-narragansett-bay\/"},"modified":"2016-04-18T00:00:00","modified_gmt":"2016-04-18T00:00:00","slug":"uri-researcher-invasive-crabs-changing-ecology-of-narragansett-bay","status":"publish","type":"post","link":"https:\/\/www.uri.edu\/news\/2016\/04\/uri-researcher-invasive-crabs-changing-ecology-of-narragansett-bay\/","title":{"rendered":"溏心vlog免费B站 researcher: Invasive crabs changing ecology of Narragansett Bay"},"content":{"rendered":"
\n\t\t\tKINGSTON, R.I. \u2013 April 18, 2016 \u2013 Niels-Viggo Hobbs has spent a great deal of time in recent years exploring tide pools and the rocky shoreline of Rhode Island, and he said that the ecology of the shore has changed dramatically in the last two decades due to one relatively recent invader: the Asian shore crab.<\/p>\n


\n\t\u201cTwenty years ago if you went to the rocky shore and turned over rocks, you would have found mostly one or two species of native crabs,\u201d said Hobbs, a doctoral candidate at the 溏心vlog免费B站. \u201cBut within a year of the Asian shore crab showing up in Rhode Island in 1998, if you turned over those same rocks, you\u2019d have something like 20 or 30 Asian shore crabs.\u201d<\/p>\n


\n\tThis dramatic change in the composition of crabs in the region may have far reaching implications for the ecology of Narragansett Bay. Many of the native crab species in Rhode Island are difficult to find. Some have been pushed into deeper water, where they are preyed upon by fish and other species they seldom encountered in the past. Others, like the spider crab, seem to be unaffected by the invaders.<\/p>\n

Asian shore crabs aren\u2019t large \u2013 their shells are typically an inch or less across \u2013 but they reproduce quickly and are more tolerant of cold and being out of the water than the region\u2019s native crabs. Hobbs said that a one-meter area that may have harbored a dozen native crabs two decades ago now harbors hundreds of Asian shore crabs.<\/p>\n


\n\t\u201cThey eat whatever they can get their claws on, and they reproduce like crazy, so they have a lot of mouths to feed,\u201d Hobbs said. \u201cBut they also become food for other marine life as well.\u201d<\/p>\n


\n\tLobsters are one such species for which the Asian shore crab is a double-edged sword. While the shore crabs may consume large quantities of larval lobsters, the crabs are also probably eaten in large numbers by adult lobsters. Commercially important fish, such as black sea bass, also benefit from the availability of large quantities of Asian shore crabs.<\/p>\n


\n\tHobbs said the green crab, which is the second most abundant crab species on Narragansett Bay shores, is also an invasive species. But it arrived in the region in the ballast of ships about 200 years ago \u2013 long before scientists paid much attention to crabs — so it is difficult to know how its arrival may have affected the marine environment.<\/p>\n


\n\t\u201cThe one thing we know happened after the arrival of green crabs is that snail shells got thicker and tougher,\u201d Hobbs said. \u201cThey were apparently really good at cracking open snail shells, so the snails evolved thicker shells.\u201d<\/p>\n


\n\tThe focus of Hobbs\u2019 research is on the cost of aggression among crabs of the same species \u2013 for instance, how does fighting among themselves affect how quickly they grow and mature, how likely they are to be injured or die, and other factors. So he put pairs of crabs in glass jars for what he called \u201ccrab fight club\u201d to observe how aggressively they behaved.<\/p>\n


\n\tHe found a great deal of variation. Spider crabs, which have the smallest claws, exhibit almost no aggression at all, whereas the rare lady crab is just the opposite.<\/p>\n


\n\t\u201cThose results likely correlate with how abundant they are in the wild,\u201d explained Hobbs. \u201cHundreds of spider crabs can be piled up in one small area, and if they were as aggressive as lady crabs then they would just kill each other.\u201d<\/p>\n


\n\tWhat is most interesting to Hobbs is that Asian shore crabs aren\u2019t all that aggressive. Since they don\u2019t fight among themselves, they can rapidly build up large populations, making it difficult for native crabs to share the same habitat.<\/p>\n


\n\t\u201cOne of the major mechanisms helping the Asian shore crab succeed is that they\u2019re not all that aggressive to their own species,\u201d Hobbs said. \u201cThey\u2019re incredibly tolerant of other Asian shore crabs, allowing them to be in such abundance that they can act like a wall keeping other species from moving into an area.\u201d<\/p>\n


\n\tHas the invasion of Asian shore crabs and green crabs made the Narragansett Bay ecosystem unhealthy?<\/p>\n


\n\t\u201cI can\u2019t say it\u2019s a less healthy ecosystem; it\u2019s just a different ecosystem than it would have been without them,\u201d Hobbs said. \u201cThere could be negative ecosystem effects \u2013 in addition to outcompeting native crabs, Asian shore crabs eat a lot of mussels, so they could be having an effect on important filter feeders in the bay. But there is no evidence that they\u2019ve had such an impact that the ecosystem changes are significantly negative. So far it\u2019s just lower level ecological communities that have been negatively affected at this point.\u201d<\/p>\n


\nShown above:

\n\u2022 溏心vlog免费B站 doctoral candidate Niels-Viggo Hobbs sorts through crabs along the Rhode Island shore.

\n\u2022 Asian shore crabs Both images are provided courtesy of Niels-Viggo Hobbs.<\/div>\n","protected":false},"excerpt":{"rendered":"

KINGSTON, R.I. \u2013 April 18, 2016 \u2013 Niels-Viggo Hobbs has spent a great deal of time in recent years exploring tide pools and the rocky shoreline of Rhode Island, and he said that the ecology of the shore has changed dramatically in the last two decades due to one relatively recent invader: the Asian shore […]<\/p>\n","protected":false},"author":2,"featured_media":58304,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[],"class_list":["post-58301","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-archives"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/posts\/58301","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/comments?post=58301"}],"version-history":[{"count":0,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/posts\/58301\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/media\/58304"}],"wp:attachment":[{"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/media?parent=58301"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/categories?post=58301"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/tags?post=58301"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}