HomeMy WebLinkAboutSubmitted by Commissioner Hearn example shellfish rating systemTo: Barnstable Conservation Commission and Barnstable Natural Resources shellfish staff
From: Bill Hearn, Barnstable Conservation Commission member
Date: March 10, 2023
Subject: Rating Shellfish Habitat
At the April 4, 2023 Conservation Commission Hearing, I mentioned that a more finely tuned shellfish
rating system would be of great help to the Conservation Commission. The current system generates a
one to ten score based on the number of “expert” surveyors that vote that a shoreline segment is
significant shellfish habitat. Thus a score of 5 may be due to five surveyors voting that it is significant,
four stating that they are unfamiliar with the segment and one voting that it is not significant. A score of
6 might be due to six surveyors voting that the segment is significant and four voting that it is not. A
more nuanced system would better inform the Commission as to the general conditions in a segment,
i.e., is it very good habitat, good habitat, fair habitat, poor habitat or just plain terrible habitat with little
prospect of ever supporting recreational or commercial harvest.
At the April 4 meeting, Commissioner Sampou suggested that we keep the system simple, that what has
been done (i.e., the previous surveys) provides some worthwhile information. In essence, we need data,
this is what has been collected, let us not dismiss it and have no data to base our decisions. I am not
opposed to that position if the Conservation Commission and Barnstable Natural Resources does not
have the time or resources to collect further data. However, I think it is very important that any score
show both the total score (number of surveyors voting that a segment is significant habitat) AND the
number of surveyors who voted “unfamiliar”. Some surveyors may not have had boat access, some
surveyors may simply never have gone to a segment simply because they harvest what they need
elsewhere. For each segment we need to know how many surveyors voted “unfamiliar” and how many
voted “significant”. Presumably those voting that the habitat is “not significant” can be calculated as the
remainder of the ten total votes.
Although I am willing to accept the above plan that allows the commission to identify “unfamiliar” votes
from those voting “not significant”, I still encourage our Commission to request additional survey work
that distinguishes different levels of habitat quality. I believe that it would be useful as a means to
monitor conditions along our shorelines over the coming decades. It would also alert us to where
conditions are especially good for shellfish, where they are of good quality, fair quality, poor quality, and
really negligible value. Below is an example of such a rating system. I would suggest that scores would
be numerically averaged (perhaps generate both the mean and median scores) among at least 8 of 10
surveyors. If one or two surveyors are unfamiliar with a segment, then their scores would not be
counted. If more than 2 surveyors are unfamiliar with a site, then a field visit should be scheduled so
that at least 8 members of the survey team can be sufficiently knowledgeable about the site. Such an
effort might take a year or two to complete, but it would be useful to us and those interested in the
long-term conditions of Barnstable shellfish habitat.
Example of scaled rating system for shellfish habitat assessments
10. Extremely, high quality, productive shellfish habitat. Some of the best in Barnstable.
9. High quality habitat likely capable of supporting relatively high densities of shellfish.
8. Good quality shellfish habitat likely capable of supporting moderate to high densities of shellfish.
7. Fair to good quality habitat capable of supporting moderate densities of shellfish.
6. Fair quality habitat likely supporting low to moderate numbers of shellfish, yet worthy of highest
protection measures.
5. Habitat likely supports low numbers of shellfish
4. Relatively low-quality habitat that may support some numbers of shellfish.
3. Poor quality habitat with likely very low production and densities of shellfish.
2. Likely no shellfish present in segment because substrate is primarily shallow (>4”) anoxic muck.
Restoration and recovery of habitat may be possible.
1. Likely no shellfish present in segment because substrate is primarily deep (>4”) anoxic muck.
Restoration or recovery of habitat is highly unlikely or not possible.