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New Bay Health, Restoration Efforts and Replacement Indicators. MASC meeting 12/18/07. New Bay Health Indicator: Menhaden Abundance. Objective: Report status of Bay-wide juvenile menhaden abundance
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New Bay Health, Restoration Efforts and Replacement Indicators MASC meeting 12/18/07
New Bay Health Indicator: Menhaden Abundance Objective: Report status of Bay-wide juvenile menhaden abundance • 2006 Narrative:“Scientists currently do not produce Chesapeake Bay-specific population estimates of menhaden. Estimates are made on an Atlantic Coast-wide basis. Populations along the Atlantic Coast appear to be healthy, but scientists are concerned about low regional abundances in Chesapeake Bay. The number of juvenile menhaden in Chesapeake Bay has been declining in recent years, with current recruitment levels being about 50% lower than the mid-1980s. In 2006, Virginia placed a cap on the amount of menhaden that can be harvested annually from the Chesapeake Bay by the commercial fishing industry. Maryland currently prohibits the commercial industry from harvesting menhaden from Maryland waters. Since menhaden are an important forage species in the Bay food web, a number of studies are underway to assess their status in the Bay.”
New Bay Health Indicator: Menhaden Abundance Considerations • Data support the following 2006 statement: “The number of juvenile menhaden in the Bay has been declining in recent years, with current recruitment levels being about 50% lower than the mid-1980s." • Indices of menhaden recruitment address how well Chesapeake Bay is serving as a nursery area for the Atlantic menhaden population (a.k.a. coast-wide stock). • However, recruitment is highly variable and not directly tied to the size of the menhaden population, nor to water quality conditions. Population abundance and water quality both influence recruitment but other factors (climate, predation, and disease) play a larger role in determining recruitment for any given year.
New Bay Health Indicator: Menhaden Abundance Recommendations • The NOAA/MD DNR Cooperative Oxford Laboratory recommends using a log geometric mean index based on Chesapeake Bay recruitment (juvenile) data. • IWG expressed a concern about distinguishing an abundance index based on recruitment in the Bay from the metrics used by ASMFC to determine the coastwide stock for fishery management purposes. It may be useful to refer to coastwide stock abundance metrics in the CBP assessment, for reference purposes and to distinguish the two abundance measures.
New Bay Health Indicator: Menhaden Abundance Recommendations (continued) • Option 1 – Use current juvenile menhaden abundance index (GMI) • Not sure of relationship of beach seine to absolute abundance in Bay • Non-linearity important • Option 2 – Proportion of Positive Hauls (PPHL) • Not influenced by very few large hauls • More responsive at low levels – might help facilitate precautionary management approach
New Bay Health Indicator: Menhaden Abundance Comments • Group preferred Option 2- (PPHL) • Comments grouped as follows: • Determining health • Data analysis • Assigning letter grades • Not recommended
New Bay Health Indicator: Tidal Wetlands Abundance Background • Objective: Report status of Bay-wide tidal wetlands, (not intended to speak about health of wetlands) • UMCES Marsh Condition Index good but expensive • Coastal Change Analysis Program (C-CAP) land cover and change maps • Suitable for monitoring on 1 to 5 year cycle
New Bay Health Indicator: Tidal Wetlands Abundance Issues • Defining tidal wetlands (includes estuarine scrub/shrub, forested, emergent wetlands) • 30m resolution – may not detect small changes (require 30,000 acre change to be significant). However, in future, CBP GIS will have capability to do high resolution verification. • Baseline will be set upon 1984 and 1992 data analysis • Probably most cost effective method
New Bay Health Indicator: Tidal Wetlands Abundance Recommendations • I
New Bay Restoration Efforts Indicator: Oyster Recovery Efforts Objective: Report status of Bay-wide oyster recovery efforts 2006 Narrative: “Oyster reefs are an essential component of the Bay ecosystem, providing healthy habitat for other bottom-dwelling organisms as well as schools of fish. Reef restoration efforts include cleaning and placing oyster shells, planting hatchery-produced spat (juvenile) oysters, setting aside permanent sanctuaries, and placing alternate substrate materials. Thousands of acres have been treated in this way, sometimes with multiple efforts. The success of these habitat restoration techniques has been limited by numerous factors including disease, fishing pressure and resulting habitat destruction, and poor water quality caused by human population growth and land use changes. For more information on oysters, please see Part One: Ecosystem Health.”
New Bay Restoration Efforts Indicator: Oyster Recovery Efforts Considerations • LIVRAW doesn’t support target/goal • Target level necessary to reach 10x increase in biomass has not been determined • Premature to establish an acreage goal • Acres of restoration is funding dependent • Option – “conduct x acres of restoration per year.”
New Bay Restoration Efforts Indicator: Oyster Recovery Efforts Recommendations • IWG recommends acres/year (stacked or solid bars) • IWG suggested extrapolating line to 2010 or annual target level equal to 1998 • LIVRAW suggested existing annual average as annual target • Both IWG and LIVRAW warn it is premature to set any target now • LRSC recommends acres/year (stacked or solid bars)
New Bay Restoration Efforts Indicator: Oyster recovery Efforts
New Bay Restoration Efforts Indicator: Oyster recovery Efforts
Potential Replacement Indicator: Shad Abundance Considerations • Objective: Report status of Bay-wide shad abundance • Original Shad abundance indicator (# fish lifted at Conowingo) not accurate representation of Baywide abundance • Proposed indicator combines peer-reviewed & historical data from four rivers (weighted) to provide bay-wide value • Note: Abundance estimates not being used to make decisions about current moratorium
Potential Replacement Indicator: Shad Abundance Considerations (Continued) • Uses ASFMC shad stock assessment • Includes two different metrics:fish passage goals (Susquehanna and James) and catch levels (Potomac and York).
Potential Replacement Indicator: Shad Abundance Recommendations • IWG and LRSC support this replacement indicator
Potential Replacement Indicator: Oyster Abundance Considerations • Objective: Report status of Bay-wide oyster abundance • Current MD monitoring not suitable to for producing estimates of absolute oyster abundance with enough precision • However, MD is funding two projects to address this concern and help move towards developing estimates of oyster abundance with adequate precision
Potential Replacement Indicator: Oyster Abundance Recommendations • Use existing indicator as interim measure until replacement has been approved (~after 2008)