Two-time world champion lightweight double scullers Julia Edward and Sophie MacKenzie have indicated they are taking a year off rowing.
The duo finished fourth in their final at the Rio Olympics.
Rowing NZ on Monday named a 56-strong summer training squad, with Cotter saying it aligns with the organisation's small boat focus, but continues the men's and women's developing eights programmes.
Experienced competitors who have competed in two or more Olympics have until November 18 to accept their place, with full-time training resuming on Lake Karapiro on November 28.
Double Olympic gold medallists Mahe Drysdale, Eric Murray and Hamish Bond fall into this category.
Less experienced rowers, who haven't contested an Olympics or only attended the Rio Games, have until October 3 to confirm their acceptance with fulltime training beginning on October 31.
New Zealand summer squad: Women: Genevieve Behrent, Kelsey Bevan, Brooke Donoghue, Emma Dyke, Kirsten Froude, Jackie Gowler, Kerri Gowler, Kirstyn Goodger, Holly Greenslade, Lucy Jonas, Jackie Kiddle, Olivia Loe, Eve Macfarlane, Zoe McBride, Georgia Nugent-O'Leary, Georgia Perry, Kayla Pratt, Grace Prendergast, Beth Ross, Rebecca Scown, Lucy Spoors, Zoe Stevenson, Ruby Tew, Kelsi Walters, Francie Turner (cox). Men: Alistair Bond, Hamish Bond, Michael Brake, George Bridgewater, Drikus Conradie, Cameron Crampton, Toby Cunliffe-Steel, Mahe Drysdale, Matt Dunham, Joshua Earl, Nathan Flannery, Isaac Grainger, Chris Harris, Finn Howard, James Hunter, Stephen Jones, Alex Kennedy, Shaun Kirkham, James Lassche, Adam Ling, Karl Manson, Robbie Manson, Eric Murray, Tom Murray, Brook Robertson, John Storey, Giacomo Thomas, Cameron Webster, Joe Wright, Sam Bosworth (cox), Caleb Shepherd (cox).