Coho Distribution and Range

Coho Distribution and Range

This CalFish Data Download contains two shapefiles, Coho_Distribution.shp and Coho_Range.shp. Below are the descriptive abstracts for each shapefile followed by links to their complete metadata. Please read the complete metadata before using these datasets.

Coho Distribution Abstract

April 2009 Version

Data Content:

Data Source:

Data Usage:

Examples of appropriate uses include:

Coho salmon recovery planning

Validating Coho distribution models

April 2009 Version

Data Content:

Data Source:

Data Usage:

Examples of appropriate uses include:

Coho salmon recovery planning

Validating Coho distribution models

April 2009 Version

This dataset represents the "Observed Distribution" for coho salmon in California by using observations made only between 1990 and the present. It was developed for the express purpose of assisting with species recovery planning efforts. The process for developing this dataset was to collect as many observations of the species as possible and derive the stream-based geographic distribution for the species based solely on these positive observations.

For the purpose of this dataset an observation is defined as a report of a sighting or other evidence of the presence of the species at a given place and time. As such, observations are modeled by year observed as point locations in the GIS. All such observations were collected with information regarding who reported the observation, their agency/organization/affiliation, the date that they observed the species, who compiled the information, etc. This information is maintained in the Aquatic Species Observation Database (ASOD) hosted by DFG Northern Region Environmental Resources Information Services (ERIS).

To develop this distribution dataset, the species observations were applied to standard 1:24k hydrographic features from the National Hydrographic Dataset (NHD). For each observation, a path was traced down the hydrography from the point of observation to the ocean, thereby deriving the shortest migration route from the point of observation to the sea. By appending all of these migration paths together, the "Observed Distribution" for the species is developed.

It is important to note that this layer does not attempt to model the entire possible distribution of the species. Rather, it only represents the known distribution based on where the species has been observed and reported. While some observations indeed represent the upstream extent of the species (e.g., an observation made at a hard barrier), the majority of observations only indicate where the species was sampled for or otherwise observed. Because of this, this dataset likely underestimates the absolute geographic distribution of the species.

It is also important to note that the species may not be found on an annual basis in all indicated reaches due to natural variations in run size, water conditions, and other environmental factors. As such, the information in this dataset should not be used to verify that the species are currently present in a given stream. Conversely, the absence of distribution linework for a given stream does not necessarily indicate that the species does not occur in that stream.

The observation data were compiled from a variety of disparate sources including but not limited to CDFG, USFS, NMFS, timber companies, and the public. Forms of documentation include CDFG administrative reports, personal communications with biologists, observation reports, and literature reviews. The source of each feature (to the best available knowledge) is included in the data attributes for the observations in ASOD, but not for the resulting linework. The spatial data has been referenced to NHD High Resolution hydrography.

For suggested data usage and constraints, citation/contact information and detailed processing and attribute information, please follow this link: Complete metadata for Coho_Distribution.shp

Coho Range Abstract

April 2009 Version

Data Content:

This data set contains all CalWater 2.2.1 Planning Watersheds (PWS) where DFG has documented coho salmon to be present during or after 1990. It was developed for the express purpose of assisting with Coho salmon recovery planning efforts. NOTE: Acreages are calculated for area inside California only.

It is important to note that this data set does not attempt to model the entire possible distribution of the species. Rather, it only represents planning watersheds intersecting the known distribution, which is based on where the species has been observed and reported. While the distribution data may indeed represent the extent of the species, generally the upstream extent of the distribution only represents the location of positive sampling or other observations.. Therefore, this data set likely represents an underestimation of the absolute geographic distribution of the species.

Data Source:

This watershed level data set was derived by intersecting Calwater planning watersheds with point and line features depicting Coho salmon distribution. These features are derived from a subset of data contained in the Aquatic Species Observation Database (ASOD), a Microsoft Access multi-species observation data capture application. ASOD is an ongoing project developed by the California Department of Fish and Game (CDFG), Northern Region, Environmental Resources Information Services with assistance from CDFG Biogeographic Data Branch and Pacific States Marine Fisheries Commission. These data are based upon confirmed observations of Coho salmon. Effort has been made to identify and correct watersheds that were erroneously selected due to inaccuracies from using data of different scales. The observation data that are the basis for the distribution were compiled from a variety of disparate sources including but not limited to CDFG, U.S. Forest Service, National Marine Fisheries Service, timber companies, and the public. Forms of documentation include CDFG administrative reports, personal communications with biologists, observation reports, and literature reviews.

This derived dataset is meant to be continually updated as additional information is acquired. As such, any copy of this dataset is considered to be a snapshot of the known Coho Distribution at the time of release. It is incumbent upon the user to ensure that they have the most recent version prior to making management or planning decisions.

For suggested data usage and constraints, citation/contact information and detailed processing and attribute information, please follow this link: Complete metadata for Coho_Range.shp