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What does "return rate" (tasa de retorno in spanish) mean in population ecology models? In context of capture-mark-recapture models. I have found many articles on this, but no definition!

I've also found the term "recapture rate". What is it? Is it the same as "return rate"?

Tomas
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  • This is may be a useful link for you along with my answer. http://xa.yimg.com/kq/groups/15759080/2001977639/name/Effects+of+toe+clipping+on+salamanders+in+Canada.pdf – Blain Waan Oct 08 '12 at 16:35
  • A second reference for the definition of recapture rate. http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CB4QFjAA&url=http%3A%2F%2Fwww.nature.com%2Fnature%2Fjournal%2Fv432%2Fn7016%2Fextref%2Fnature03039-s1.doc&ei=VhJzULbqEIrKrAeS2IDACQ&usg=AFQjCNHR-bPJ3xYBZpnSKgVUedl4kMjs4A – Blain Waan Oct 08 '12 at 17:51

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Recapture rate and survival rate are the two components of return rate. The return rate observed during a mark–recapture study is a product of the probability of survival (survival rate) and the probability of recapturing an animal that is alive (recapture rate). Recapture rate is the number of marked individuals recaptured divided by the total number of individuals captured in the second visit.

Blain Waan
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  • Thanks Blain, however the last sentence sounds suspicious to me. If you define recapture rate as probability that alive animal is recaptured, then it would be number of individuals recaptured divided by total number of alive individuals. What you said in last sentence is a ratio of marked individuals to all captured individuals. Btw, REcaptured means captured again, right? So all REcaptured individuals must be markerd, right? – Tomas Oct 08 '12 at 17:15
  • In formal definition, the marginal recapture rate for Census i is the number of individuals seen during census i that were marked during any previous Census divided by the total number of individuals seen during Census i. The same definition holds for the sample survey (instead of census) too. In capture-recapture method you assume that your second sample is representative of the first sample. So, (number of marked recaptured)/(number captured in the second visit)=(number of marked in the first visit)/(total population size). You just multiply this by the survival probability. – Blain Waan Oct 08 '12 at 17:42
  • And of course thanks for the correction. I've edited the answer. – Blain Waan Oct 08 '12 at 17:44
  • Moreover the reason why your thought about "number of individuals recaptured divided by total number of alive individuals" as being the recapture rate is not correct is that you completely ignore counting the number of marked individuals found in the 2nd visit by your definition, then why did you mark the captured ones in the first visit? You can only find the recapture rate through your 2nd sample. Right? :) – Blain Waan Oct 08 '12 at 18:17