Invasive Species

Question 1

Kideys et al (2002)

Answer 1

Black sea suffered really bad from introduction of comb jellys (Mnemiopsis) which ate larvae and completed for zooplanton. Anchovy fishery collpased and dolphin numbers reduced.

Question 2

McGinney et al (1997)

Answer 2

Wild, hybrid and farmed salmon. Farmed are much faster during early growth and displace wild salmon but consequently post smolt surival is much reduced, Therefore everyone misses out. These escaped fish are causing fitness reduction in wild populations.

Question 3

Bushmann et al (2006)

Answer 3

Intorduction of a novel food source, although not espcaped in Chilean salmon fisheries resulted in a multiple of ecosystem changes but most evidently a 5fold increase in carrion feeding birds and seabirds in the area. This is likely to cause consequntial chnages and predator-prey relationships chnage.

Question 4

Jensen et al (2009)

Answer 4

Due to all the problems and high levels of escape in Norway, the fishing regulation bought about measures to improve gear and ensure it could withstand environmental stress which is when most species escape. Once the near gear had been implemented a significant decreased in escaped fish was documented.

Question 5

Craik (1997)

Answer 5

American Mink in Scotland caused significant decline in black-banded and common gulls as well as common terns. Surverys revealed that populations dcreased by 54%, 30% and 36% respectively after the mink arrived on the west coast of scotland. All colonies were visited once during breeding season and the bigger colonies twice to sensure complete counts.

Question 6

Hughes et al (2007)

Answer 6

Ascension Island. Sooty shearwaters monitored over 17 year period which was coincided with a cat eradicaiton programme. It was shown that their number increased by 48% in the first year it was cat free, and then 8,6% in the following years.

Question 7

Caut et al (2007)

Answer 7

Surprise Island in New Caledonia. Rats heavily preyed upon seabirds but as their numbers declined their abundance reduced and rats moved on to hunting sea turtle eggs. Demonstrates problems with eradication when they have flexible feeding patterns.

Question 8

Molnar et al (2008)

Answer 8

329 invasive species, only 16% of marine ecoregions have not reported some kind of invasive species. Can displace native species, change community structur and food webs as well as cause huge economic damage. Crustaceans and molluscs are the majority.