Ecosystems

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Question 24

Marine biologists are studying a coastal conservation zone consisting of three distinct benthic habitats:

Seagrass meadow: $m21400\text{ m}^2$
Kelp forest: $m21600\text{ m}^2$
Sandy reef: $m21000\text{ m}^2$

Suppose the biologists want to carry out representative stratified sampling using a total of 80 sample sites. Calculate the number of sample sites that should be allocated to each habitat type, and explain how the sample locations within each habitat should be chosen.

[4]

The biologists used the capture-mark-recapture technique to estimate the populations of two marine species: the spiny lobster and the seahorse. They used two different population estimators:

Lincoln estimate formula:

\text{Population size} = \frac{n1 \times n2}{m}

Chapman estimate formula:

\text{Population size} = \left(\frac{(n1 + 1) \times (n2 + 1)}{m + 1}\right) - 1

where:

$n 1$ = number of individuals captured and marked in the first sample
$n 2$ = total number of individuals captured in the second sample
$m$ = number of marked individuals recaptured in the second sample

The table below shows the data collected:

Species	Number captured and marked in sample 1 ( $n 1$ )	Total number in sample 2 ( $n 2$ )	Number of marked individuals in sample 2 ( $m$ )
Spiny lobster	95	92	8
Seahorse	11	14	3

Calculate the population estimates for both species using both the Lincoln and Chapman formulas. Round all final answers to the nearest whole number.

[6]

Ecosystems

Question 24

Ecosystems Questions

Ecosystems

Question 24

Ecosystems Questions