Population growth rate, abundance and distribution of marine mammals

Population growth rate. Population growth rate should be positive until hampered by natural limitations. Deviations during the phase of exponential increase are indicative of that the population is reaching its carrying capacity or is affected by human impacts. Near the carrying capacity, the population fluctuates but a continuous decline indicates that the population is not in good environmental status (GES).

Abundance. Population abundances of the marine mammals are informative indicators of the state of the populations.

Distribution. The abundance of populations in different parts of the Baltic Sea gives an indication of the distribution of the population.

Population growth rate, abundance and distribution of marine mammals

Stage of development Indicator typeCore State

Primary importance Secondary importanceBSAPSegment and Objective

Biodiversity- Healthy wildlife

Biodiversity:- Thriving and balanced communities of plants and animals- Viable populations of speciesHazardous Substances:- Concentrations of hazardous substances close to natural levels

MSFD Descriptors and Criteria

D1. BiodiversityD1.3. Population condition

D1. Biodiversity D1.1 Species distribution (range, pattern, covered area) D1.2 Population size (abundance, biomass)D4. Food webs D4.1. Productivity of key species or trophic groups D4.3 Abundance/distribution of key trophic groups/speciesD8. Contaminants D8.2. Effects of contaminants

Other relevant legislation: (WFD - Chemical quality, Habitat directive

Legislative linkage:

Population growth rate, abundance and distribution of marine mammals

Concept/design

Coordinated monitoring Assessment

Research needs for operationalization (in

relation to needs stated under the

coordinated monitoring and

assessment columns)

Data arrangements

Monitoring strategy (method, frequency, spatial resolution) in relation to relevant indicator parameters Technical guidelines Geographic scale

Assessment method

GES / assessment criteria(currently all GES are provisional)

A ) in placeB) under developmentC ) not available, what needs - action level?

A ) monitoring in placeB ) monitoring needs revisionC ) monitoring not available, what needs - action level?

A ) in placeB ) needs revision, what needs doingC ) not available, what needs - action level?

HELCOM assessment units:A ) identifiedB) Identified not describedC) not identified, what needs - action level?

A ) available and describedB ) available not describedC ) not available, what needs - action level?

A ) proposed and describedB ) proposed but needs more supporting dataC ) not available, what needs - action level? A ) in place

B ) needs revision, what needs doingC ) not available, what needs - action level?

B for seals but not for harbour porpoises

B for seals C for harbour porpoises

B for grey and seals but B for ringed seals in EstoniaC for harbour porpoises.

A for all species A for grey and harbour seals B for ringed seals in Estonia and GOFC for harbour porpoises.

B for seals C forharbour porpoises

B for seals but not for harbour porpoises

A for seals C for harbour porpoises

A for sealsC for harbour porpoises

A for grey and seals but B for ringed seals in EstoniaC for harbour porpoises.

A for all species A for grey and seals but B for ringed seals in EstoniaC for harbour porpoises.

A for seals C for harbour porpoises

Ringed seals in Estonia: Investigate alternative methods since counts on ice are not applicable in a majority of years.Harbour porpoise: Investigate alternative methods

A for seals C for harbour porpoisesEx

ampl

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for

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rent

situ

ation

(action level = who needs to complete the task)

Population growth rate, abundance and distribution of marine mammals

• GES: At the moment all the populations are assessed against their intrinsic growth rate during exponential growth:

• Grey seals and ringed seals: 10 % intrinsic growth rate.

• Harbour seals: 12 % intrinsic growth rate.

• Harbour porpoise: 4 % intrinsic growth rate.

• At Carrying capacity: No decline exceeding 5% over a period of six years

• No decline in distribution

People involved: Tero Härkönen, Karin Hårding, Olle Karlsson, Anders Galatius, Markus Ahola.

0,8

0,85

0,9

0,95

1

0,8 0,85 0,9 0,95 1

Annual juvenile survival (0-3 years)

An

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Ann

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Population growth rate, abundance and distribution of marine mammals

• HELCOM Assessment Unit Level: 1

• The indicator is applicable in: All of the Baltic for grey seals, the Bothnian Bay, the Gulf of Finland and the Estonian coastal waters for ringed seals. Southern Baltic and the Kattegat for Harbour seals.

• Currently data is available : Available for all seal species, but not for harbour porpoises

Population growth rate, abundance and distribution of marine mammals

List of issues that still need to be solved for the indicator

Describe what is hindering solving the issue

Ringed seal abundance and distribution in the Gulf of Finland and the Gulf of Riga

Ice situation has changed such that surveys during moult on ice are not possible during most winters. Need to investigate if counts of seals hauled out during lautumn can be used instead.

Abundance of harbour porpoises Survey method not applicable when abundance is very low. Need for developing other e.g. acoustic methods.

Population growth rate, abundance and distribution of marine mammals

- Temporal trends in weaning weights of grey seal pups.

- -Autumn weights of pups of the year in harbour seals

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

15 20 25 30

Autumn weight of pups (kg)

Su

rviv

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rob

ab

ilit

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0

5

10

15

20

25

30

35

40

50 70 90 110 130 150 170 190 210

Age at capture (days)

We

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ap

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(k

g)

FUTURE INDICATORS