Ecosystem impacts of fishing and Ecosystem Based Management

1
Ecosystem impacts of fishing and Ecosystem Based
Management

• Fish 323

2
Views of Ecosystems
3
Trophic
4
Ecosystem structure

• Refuge from predators
• Access to food

5
(No Transcript)
6
The California Current Ecosystem
7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
San Miguel Island Fur Seal
U.S. PACIFIC MARINE MAMMAL STOCK ASSESSMENTS
2005Carretta et al. NOAA Technical Memo
NOAA-TM-NMFS-SWFSC-388
15
(No Transcript)
16
(No Transcript)
17
Maximum biomass of key commercial species in the
ecosystem
18
None of these stocks are overfished no lost
yield

• These stocks constitute 97 of the biomass!
• All of the overfished stocks are low abundance
  stocks, they constitute 1.3 of the unfished
  stock biomass
• Widow classified as overfished but at 31 of
  unfished biomass

19
Maximum biomass of less abundant species
20
The overfished stocks
21
Revenue (constant )from Little et al
22
History of catch
From Little et al
23
Ecosystem goods and services what we value

• Food
• Commercial value in harvest
• Recreational harvest
• Recreational non-consumptive use
• Existence value
• Non food products, pharmaceuticals
• Water quality climate

24
A score-cardhow are we doing

• Yield for food, communities and jobs
• Profitability
• Abundance in recreational areas
• Abundance of charismatic species
• Lack of extinction

25
What does fishing do?

• Reduces abundance of target species
• Reduce abundance of non-target species due to
  by-catch
• Increased abundance of some non-target species
• Modify habitat due to physical action
• Change trophic levels
• Encourage invasive species

26
Bottom Trawling
27
http//www.youtube.com/watch?vzikSzUhUGtA
28
Photos Keith Sainsbury
29
What is known

• Bottom contact gear has large impact on benthic
  structure
• It does not appear to modify sand-mud bottom as
  much, or even at all

30
Heike Lotze meta analysis
31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
Key points to note

• These systems are dramatically transformed
• Some elements of the ecosystem are more impacted
  than others
• The fishes are generally in the range of BMSY
  (surprisingly)

35
Ecosystem based management
An ecosystem approach to management (EAM) is one
that provides a comprehensive framework for
living resource decision making. In contrast to
individual species or single issue management,
EAM considers a wider range of relevant
ecological, environmental, and human factors
bearing on societal choices regarding resource
use.From NOAA
36
EAM is differentiated from more narrowly focused
management approaches by a number of defining
characteristics. EAM is (1) geographically
specified, (2) adaptive in its development over
time as new information becomes available or as
circumstances change, (3) takes into account
ecosystem knowledge and uncertainties, (4)
recognizes that multiple simultaneous factors may
influence the outcomes of management
(particularly those external to the ecosystem),
and (5) strives to balance diverse societal
objectives that result from resource decision
making and allocation. Additionally, because of
its complexity and emphasis on stakeholder
involvement, the process of implementing EAM
needs to be (6) incremental and (7) collaborative
(Sissenwine and Murawski 2004).
37
Elements of EBMfrom the Convention on Biological
Diversity

• The objectives of management of land, water and
  living resources are a matter of societal
  choices,
• Management should be decentralized to the lowest
  appropriate level,
• Ecosystem managers should consider the effects
  (actual or potential) of their activities on
  adjacent and other ecosystems,
• Conservation of ecosystem structure and
  functioning, in order to maintain ecosystem
  services, should be a priority target of the
  ecosystem approach,
• Ecosystem must be managed within the limits of
  their functioning,
• The ecosystem approach should be undertaken at
  the appropriate spatial and temporal scales,

38
More elements

• Recognizing the varying temporal scales and
  lag-effects that characterize ecosystem
  processes, objectives for ecosystem management
  should be set for the long term,
• Management must recognize the change is
  inevitable,
• The ecosystem approach should seek the
  appropriate balance between, and integration of,
  conservation and use of biological diversity,
• The ecosystem approach should consider all forms
  of relevant information, including scientific and
  indigenous and local knowledge, innovations and
  practices,
• The ecosystem approach should involve all
  relevant sectors of society and scientific
  disciplines.

39
Some hard questions

• What do we do about trophic tradeoffs

40
Walters vision of alternative tradeoffs based on
his experience with ecosystem analysis
The concave tradeoff hypothesis (better
support by data, models)
The convex tradeoff hypothesis (belief,
pretense, hope, wishful thinking)
Compromise sacrifices much of both values
Non-consumptive Value
Fishery Value
41
Walters analysis of cod-shrimp tradeoff
42
Competing demands

• Commercial fishing including trawling
• Recreational fishing
• Non-consumptive use (diving, whale watching)
• Aquaculture

43
The proposed solution

• Ocean zoning
• Is currently used (aquaculture leases) and will
  certainly grow
• Marine protected areas
• Recreational reserves

44
(No Transcript)
45
(No Transcript)
46
How is EBM applied in actual fisheries

• By-catch reduction
• Closure of sensitive areas
• Explicit consideration of trophic connection
• Move to single species reference points with
  lower exploitation rates